
The Thomas Fire was a massive
wildfire
A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...
that affected
Ventura and
Santa Barbara Counties, and one of
multiple wildfires that ignited in
Southern California
Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...
in December 2017. It burned approximately before being fully contained on January 12, 2018, making it the largest
wildfire in modern California history at the time. It was surpassed by the Ranch Fire, part of the
Mendocino Complex, in August 2018.
The fire is currently the eighth-largest wildfire in modern California history, as of 2025. The fire was officially declared out on June 1, 2018, after more than two months in which no hotspots were detected.
The Thomas Fire destroyed at least 1,063 structures, while damaging 280 others;
and the fire caused over $2.2 billion (2018 USD) in damages,
including $230 million in suppression costs,
becoming the seventh-most destructive wildfire in state history at the time.
As of August 2020, the Thomas Fire is California's tenth-most destructive wildfire.
Ventura's agriculture industry suffered at least $171 million in losses due to the Thomas Fire.
By January 2, 2018, the Thomas Fire had cost over $204 million to fight,
and had forced over 104,607 residents to At its height, the Thomas Fire saw over 8,500 firefighters mobilized to fight it, which is the largest mobilization of firefighters for combating any wildfire in California history.
The fire began on December 4, north of
Santa Paula, near Steckel Park and south of
Thomas Aquinas College from which the fire was named. Fast-moving, it quickly reached the city of
Ventura, where over five hundred residences were destroyed that night.
The fire destroyed almost as many residences in several rural communities amidst the rugged mountain terrain of Ventura County. The fire threatened the
Ojai Valley, and on December 13, the fire completely surrounded the area, including
Lake Casitas.
The fire began burning through the rugged
Santa Ynez Mountains
The Santa Ynez Mountains are a portion of the Transverse Ranges, part of the Pacific Coast Ranges of the west coast of North America. It is the westernmost range in the Transverse Ranges.
The range is a large fault block of Cenozoic age created ...
as it threatened several small communities along the Rincon Coast north of Ventura, expanded into the
Los Padres National Forest
Los Padres National Forest is a United States national forest in Southern California, southern and central California. Administered by the United States Forest Service, Los Padres includes most of the mountainous land along the California coast ...
, and reached Santa Barbara County. Firefighters concentrated on protecting the communities of Carpinteria and Montecito in the southern portion of the county as the fire burned in the foothills of the Santa Ynez Mountains where access was difficult.
The unusually strong and persistent
Santa Ana winds
The Santa Ana winds, occasionally referred to as the devil winds, are strong, extremely dry katabatic winds that originate inland and affect coastal Southern California and northern Baja California. They originate from cool, dry high-pressure ...
were the largest factor in the spread of the fire.
Much of Southern California experienced "the strongest and longest duration Santa Ana wind event we have seen so far this season", according to the National Weather Service.
The region experienced an on-and-off Santa Ana wind event for a little over two weeks, which contributed to the Thomas Fire's persistent growths in size.
At its height, the wildfire was powerful enough to generate its own weather, qualifying it as a
firestorm
A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used ...
.
There were periods of time when the fire was advancing at a rate of an acre (0.4 ha) per second.
The winds also dried out the air, resulting in extremely low humidity.
The area, along with most of Southern California, experienced the driest March-through-December period on record.
While November is the typical beginning of the rainy season in California, the first measurable rain for the area fell on January 8, 2018, more than a month into the fire. With the natural vegetation burnt,
flash flood
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice and snow. Flash f ...
s and
mudflow
A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/se ...
s damaged homes in Montecito when the rains arrived. Evacuations were ordered or anticipated for neighborhoods that sit below areas recently burned by the Thomas Fire and other wildfires.
By January 10, at least 21 people had been killed by the
sudden flooding and debris flows that followed the heavy rains, which also destroyed over 100 homes.
Progression
December 2017
On December 4, 2017, the fire was first reported by a nearby resident at 6:26 p.m.
PST,
to the north of
Santa Paula, near Steckel Park and
Thomas Aquinas College,
after which the fire is named.
That night, the small brush fire exploded in size and raced through the rugged mountain terrain that lies west of Santa Paula, between Ventura and Ojai.
Officials blamed strong
Santa Ana winds
The Santa Ana winds, occasionally referred to as the devil winds, are strong, extremely dry katabatic winds that originate inland and affect coastal Southern California and northern Baja California. They originate from cool, dry high-pressure ...
that gusted up to for the sudden expansion.
Soon after the fire had started, a second blaze was ignited nearly 30 minutes later, about to the north in
Upper Ojai at the top of Koenigstein Road.
According to eyewitnesses, this second fire was sparked by an explosion in the power line over the area. The second fire was rapidly expanded by the strong Santa Ana winds, and soon merged into the Thomas Fire later that night.
According to statements released by investigators on March 13, 2019,
Southern California Edison
Southern California Edison (SCE), the largest subsidiary of Edison International, is the primary electric utility company for much of Southern California. It provides 15 million people with electricity across a service territory of approximate ...
was responsible for both ignitions.
Late on the night of December 4, the Thomas Fire reached the hillside neighborhoods of Clearpoint, Ondulando, and Skyline in the city of Ventura and destroyed many
single-family detached home
A single-family detached home, also called a single-detached dwelling, single-family residence (SFR) or separate house is a free-standing residential building. It is defined in opposition to a multi-family residential dwelling.
Definitions ...
s. Many people fled with little or no warning when evacuation orders were issued, as the fire had traveled in just a few hours.
Tuesday morning, on December 5, saw 1,000 firefighters battling the blaze, with no containment of the fire. At 7 a.m. PST, one
helicopter
A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...
began dropping water, while fixed-wing aircraft waited to be deployed after the winds died down.
The firefighters tried to save Ventura homes in the midst of a
red-flag wind advisory with ridgeline winds of and gusts up to .
The fire continued jumping across the valleys along the steep slopes of the
foothills
Foothills or piedmont are geography, geographically defined as gradual increases in elevation at the base of a mountain range, higher hill range or an highland, upland area. They are a transition zone between plains and low terrain, relief hill ...
that abut the northern portion of the city. As the fire traveled along the interface between the foothill
rangeland
Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savanna ...
and the area developed with homes, it reached the hills above downtown where several apartment buildings and other homes above downtown Ventura were damaged or completely destroyed.
The fire burned over Grant Park above
City Hall
In local government, a city hall, town hall, civic centre (in the UK or Australia), guildhall, or municipal hall (in the Philippines) is the chief administrative building of a city, town, or other municipality. It usually houses the city o ...
, and burned along the ridge above the western portion of the city, which stretches north along the narrow
Ventura River
The Ventura River, in western Ventura County in southern California, United States, flows from its headwaters to the Pacific Ocean. The smallest of the three major rivers in Ventura County, it flows through the steeply sloped, narrow Ventura ...
valley, and is characterized by steeply-sloped sides.
The fire continued moving north up the valley throughout the day. The entire community of
Casitas Springs, which lies northwest of Ventura, had a mandatory evacuation issued as the fire approached.
The fire reached Black Mountain overlooking Ojai. The entire Ojai Valley was given mandatory or voluntary evacuation orders. The Ojai pumping system was damaged by the fire and the entire water system stopped working for a time so water was not available from the hydrants for use by the firefighters. The western flank of the fire jumped over Highway 33 and burned through the Taylor Ranch oil fields on the other side of the valley. The fast-moving, wind-driven wildfire continued past the area that had burned in the 2015 Christmas Day
Solimar Fire, before crossing the
101 Freeway to the Solimar Beach area, on
Pacific Coast Highway, along the Pacific Ocean. The fire continued its northwesterly march along the Rincon Coast to
Rincon Point, at the Santa Barbara County/Ventura County line.
On Tuesday, December 5, additional National Guard helicopters were brought in to fight the six largest wildfires burning in
Southern California
Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...
. Officials said they also obtained "every last plane we could find in the nation."
C-130 airplanes were obtained from the
U.S. military
The United States Armed Forces are the military forces of the United States. U.S. federal law names six armed forces: the Army, Marine Corps, Navy, Air Force, Space Force, and the Coast Guard. Since 1949, all of the armed forces, except th ...
, and more than 290 fire engines came from Montana, Utah, New Mexico, Idaho, Arizona, Oregon, and Nevada.
On December 7, the Thomas Fire grew further to , with containment of the fire at 5%.
On December 8, the Thomas Fire grew to with containment of the wildfire increasing to 10%, after the Santa Ana winds died down.
On December 9, as the Santa Ana winds returned, the Thomas Fire expanded to , while containment of the fire increased to 15%. By the afternoon of the same day, the fire entered
Santa Barbara County
Santa Barbara County, officially the County of Santa Barbara (), is a county located in Southern California. As of the 2020 United States census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa M ...
near Divide Peak.
Early on December 10, the Thomas fire expanded to , but containment of the blaze stayed the same as the previous date, at 15% total containment. The evacuation orders were expanded further north into Santa Barbara County into the communities of
Carpinteria and
Montecito.
Only the southern and southeastern flanks of the wildfire had been contained.
However, by the evening of the same day, the powerful Santa Ana winds had caused the Thomas Fire to undergo another period of explosive growth, expanding to in size, with containment dropping to 10% overall, indicating no new progress in fire containment.
Another firefighter was injured, when he fractured his leg, and he returned home to recover.
On the same day, fire analysts stated that the Thomas Fire had been generating its own weather for the past two days, a behavior only observed in very massive wildfires and indicative of a
firestorm
A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used ...
.
The Thomas Fire was generating massive
pyrocumulus clouds, which were gathering heat from the flames below, although the unstable column of air could collapse at any time, which would generate sudden wind shifts near the fire and pose a major hazard to firefighters. This behavior had been previously observed during the massive 2009
Station Fire in Los Angeles.
At this point, the Thomas Fire had become the fifth-largest wildfire in modern California history
and the largest wildfire recorded in California in December.
The Thomas Fire was also estimated to be at least the 10th most destructive wildfire on record in California.
On the morning of December 11, the Thomas Fire had grown to , while containment of the fire had increased to 15%.
After this expansion in size, the Thomas Fire's northwestern flank almost linked up with its southwestern flank, to the east of Carpinteria, cutting across parts of
Route 150, and threatening to envelop
Ojai and
Lake Casitas.
By this time, the Thomas Fire had grossly surpassed the size of the previous largest fire in December, which was extremely unusual.
Fire officials noted that many areas had been "Moonscaped", an event in which the brush has been so completely burned that it was left looking like a barren and blackened landscape, resembling the surface of the
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
, which is indicative of extreme fire behavior.
During the evening of December 11, the Thomas Fire expanded further to , while firefighters increased containment of the fire to 20%.
On December 13, the Thomas Fire's expansion slowed on its west flank, as it reached the burn area of the from 2007. However, the Thomas Fire's northwestern and southwestern flanks merged on the western shore of
Lake Casitas, completely encircling the lake and the Ojai area.
Firefighters have expected the fire's growth to be disrupted if it reaches the burn scars of other previous fires to the west within the last 10 years: the
Tea
Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of '' Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of south-western China and nor ...
,
Jesusita,
Gap, and
Rey Fires.
On December 14, the Thomas Fire expanded further to , surpassing the Zaca Fire to become the fourth-largest wildfire in modern California history. Later on the same day, the Thomas Fire expanded further to . On the same day, a Cal Fire Engineer (Cory David Iverson) died, while working northwest of Fillmore, on a flareup near the eastern flank of the fire.

On the morning of December 15, containment lines in the Santa Barbara and Montecito areas and protecting nearby homes was the priority, in addition to the threatened Carpinteria and
Summerland areas. Officials feared the
sundowner winds
A sundowner is a northerly offshore wind in California along the southern Pacific slope of Santa Ynez Mountains, in communities along the Gaviota Coast and Santa Barbara towards but not including Ventura County.
Formation
It occurs when a regio ...
could push the fire into those communities as they blow south from the mountains down to the coast, and because they also dry out the air.
Although they prevented the fire from reaching the community, it still grew to with 40% containment on the morning of December 16, surpassing the
Rim Fire
Rim may refer to:
*Rim (basketball), the hoop through which the ball must pass
**Breakaway rim, a sprung basketball rim
*Rim (coin), the raised edge which surrounds the coin design
*Rim (crater), extending above the local surface
*Rim (firearms), ...
in size, and becoming the third-largest wildfire in the modern history of California.
Around this time, officials and experts feared that the Thomas Fire could surpass the
Santiago Canyon Fire of 1889, which had burned over , and is believed to be California's all-time largest wildfire on record.

On December 17, the Thomas Fire expanded to , with 45% containment, reaching the burn scar of the 2008
Tea Fire and the 2009
Jesusita Fire
The Jesusita Fire was a wildfire that started on May 5, 2009, in the hills of Santa Barbara, California in the western United States. By the time the fire was contained on May 18 it had burned , destroyed 80 homes and damaged 15 more before be ...
.
However, the weakening of Santa Ana winds in the evening allowed firefighters to make progress on containing the fire, with firefighters able to keep the Thomas Fire from burning southward into the majority of nearby homes, and they also attacked the western front of the fire.
On December 18, firefighters began a large
firing operation north of the Thomas Fire, south of
Route 33, in order to clear away excess brush, and to attempt to control the Thomas Fire's northward expansion.
Firefighters hoped that the winds would push the control fires southward, away from the highway and towards the main body of the Thomas Fire. Fire officials stated that the
control burns could scorch up to , before they connect with the main portion of the Thomas Fire.
On December 19, the Thomas Fire grew to , with 55% containment, surpassing the burn area of the
Rush Fire in California to become the second-largest wildfire in modern California history.
On December 21, all evacuation orders for Santa Barbara County were lifted, as firefighters continued to make progress on containing the wildfire.
By this point, the Thomas Fire had become the 7th most destructive wildfire in California history.
During the evening of December 22, the Thomas Fire expanded to , with containment remaining at 65% for the second day, surpassing the
Cedar Fire of 2003 to become California's largest wildfire in modern history.
By this point, however, fire officials stated that any further growths in the fire's size would likely be due to control burns from firing operations, due to more favorable weather conditions for firefighting.
Due to the cooler temperatures and increase in humidity, the control fires were not spreading as intended, so firefighters used flamethrowers to spread the control flames manually.
On December 23, fire growth paused, and containment of the wildfire was brought up to 70%.
By the evening of the same day, firefighters had completed firing operations near the northwestern flank of the Thomas Fire, with no more planned for the time being.
However, on December 24, the Thomas Fire grew to , after the fires from the back-burning operations completely merged into the Thomas Fire,
though containment of the wildfire also increased to 86%.
The Thomas Fire had ignited about 30
oil seep fires within the fire perimeter, at the Upper Ojai area. Fire officials had ordered a foam product to help extinguish the oil seep fires, though officials warned that the products may cause more smoke upon application.
Favorable weather conditions continued, with a few snow flurries precipitating over the Thomas Fire on the same day.
On December 26, the Thomas Fire remained at ; no further growth in the fire's size was anticipated at this point.
The number of firefighters deployed decreased to about 900, and containment of the Thomas Fire increased to 88%.
That same day, CAL FIRE released a chart with the top 20 largest wildfires in California history, adding the Thomas Fire as the new largest fire.
On December 27, the Thomas Fire experienced another small expansion in size on its northeastern flank, to , while containment of the wildfire increased to 91%.
Early on December 29, the Thomas Fire was 92% contained, with no further increases in size.
On the same day, a smoldering area within the western edge of the Thomas Fire's perimeter, near Gibraltar Road, flared up, sending smoke over Santa Barbara. However, firefighters were able to extinguish the new flames by 1 p.m. PST on the same day.
On December 30, incident command was transferred to a local team headed by the Los Padres National Forest staff, and the Thomas Fire remained at 92% containment.
At that time, fire officials decided to let the remaining flames within the Thomas Fire's perimeter burn out; afterward, full containment of the wildfire was not expected until January 21, 2018.
January–March 2018
On January 8, 2018, a
winter storm
A winter storm (also known as snow storm) is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental and subarct ...
began moving ashore in California, bringing heavy rain to Southern California and prompting mandatory evacuations in parts of
Los Angeles
Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...
, Santa Barbara, and Ventura Counties, over potential mudslides in areas affected by wildfires. The storm intensified on the following day, with at least of rain falling over the two-day period, before the rainfall ended on January 9, causing
several major mudflows.
On January 12, 2018, the U.S. Forest Service declared the Thomas Fire 100 percent contained, at 281,893 acres.
Afterward, Los Padres National Forest officials continued monitoring the burn area of the Thomas Fire for hotspots. On March 22, 2018, InciWeb declared the Thomas Fire to be inactive and ceased providing updates.
On June 1, 2018, the Thomas Fire was officially declared to be out, after more than two months in which no hotspots were detected within the perimeter of the burn area.
Firefighting effort
Helicopter base of operations
The
Santa Paula Airport became a
helibase for CAL FIRE by the morning after the fire started. The airport was outfitted as a base of operations for the
water-dropping helicopters, and closed to all of the regular
general aviation
General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations except for commercial air transport or aerial work, which is defined as specialized aviation services for other ...
operations. About 23 helicopters began operating out of the airport, along with the necessary support crews,
tanker trucks, and other equipment. In addition to water, brightly colored
fire retardant
A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants ...
was dropped on the fire from the air.
During the first couple of weeks, there had been limited ability to use fixed-wing air tankers and VLAT (very large air tankers) to drop fire retardant, due to the smoky skies.
After having been in the air all day, the helicopters undergo maintenance at night. Other activities included a daily briefing each morning, lunches, and distributing maps.
Aircraft/airdrop base of operations
Many aircraft and their operations moved to other airports, such as
Camarillo
Camarillo ( ) is a city in Ventura County, California, United States. As of the 2020 United States census, the population was 70,741, an increase of 5,540 from the 65,201 counted in the 2010 Census. Camarillo is named for brothers Juan and ...
, which remained open to normal activities, while being involved in firefighting efforts. Amid all this, the Santa Paula airport was able to make one of its
hangar
A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...
s available for cats after one of the local
animal shelter
An animal shelter or pound is a place where stray, lost, abandoned or surrendered animals – mostly dogs and cats – are housed. The word "pound" has its origins in the animal pounds of the agricultural communities, where stray livestock w ...
s was filled to capacity, and for one local family with its dogs for three nights, on its premises as well.
Additionally, The Channel Islands Air National Guard
146th AW MAFFS
The Modular Airborne FireFighting System (MAFFS) is a self-contained unit used for aerial firefighting that can be loaded onto both military cargo transport Lockheed C-130 Hercules and Embraer C-390 Millennium, which then allows the aircraft to b ...
unit was activated for airdrops and served as an incident command center for aerial operations.
Out-of-state mutual aid

A total of ten strike teams from across the state of
Oregon
Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
deployed to help California firefighters battle multiple massive blazes north of Los Angeles, including the Thomas Fire. On December 6, 2017, The Oregon Fire Marshal announced the dispatching of heavy equipment (around 75 fire engines) to help.
Strike teams from Oregon arrived from Clackamas, Klamath, Lane, Linn, Marion, Multnomah, Washington and Yamhill Counties; in addition, a combined team from Benton, Linn, and Polk Counties, and a team from the Rogue Valley area were also assisting. State fire officials announced that five additional strike teams would be deployed on the evening of Wednesday, December 6.
Firefighters from Arizona,
Washington, Idaho,
Montana, New Mexico,
Nevada,
Colorado,
and Utah
were also assisting in the fire suppression efforts.
A sport utility vehicle and pickup truck were donated to the Ventura City Fire Department by
Direct Relief, a nonprofit emergency response organization, in an effort to support emergency response efforts during the Thomas Fire.
Effects
Casualties
One firefighter died of
thermal injuries and
smoke inhalation
Smoke inhalation is the breathing in of harmful fumes (produced as by-products of combusting substances) through the respiratory tract. This can cause smoke inhalation injury (a kind of acute inhalation injury) which is damage to the respirator ...
on December 14, in an active area of the fire near Fillmore, and one firefighter was injured after being struck by a car on December 5. His injuries were not considered to be life-threatening.
One person, a 70-year-old woman, died in a car accident while fleeing the fire on Wednesday night, December 6.
Damage
At least 1,063 structures have been destroyed in the fire. Numerous single-family homes were destroyed along with the Hawaiian Village Apartments in the hills above downtown Ventura and 12 houses for guest workers of
Limoneira Co. near Santa Paula. The downtown Harbor View Apartments and the Vista del Mar hospital (a psychiatric facility) on the west side of Ventura were among the complexes that were heavily damaged.
The
Ojai Valley School, near the city of Ojai, was heavily damaged with two buildings being destroyed. The Thomas Fire destroyed multiple expensive homes in the Montecito area. On December 23, the Thomas Fire was estimated to have caused over $120 million in property losses, in Santa Barbara County.
Over a quarter million
Southern California Edison
Southern California Edison (SCE), the largest subsidiary of Edison International, is the primary electric utility company for much of Southern California. It provides 15 million people with electricity across a service territory of approximate ...
customers lost power as a result of damage from the fire. The transmission system which runs from Ventura County to
Goleta had to be shut down to prevent further problems until Edison employees could safely access the area for inspections.
An
amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ...
site on Reeves Road in Ojai was heavily damaged by the fire. The site is part of a repeater network run by
amateur radio operator
An amateur radio operator is someone who uses equipment at an amateur radio station to engage in two-way personal communications with other amateur operators on radio frequencies assigned to the amateur radio service. Amateur radio operators ...
s. These volunteers plan to replace lost equipment and enhance the shared station with additional cameras, solar panels, batteries, a weather station, and other hardware.
Closures and evacuations
Dozens of school districts implemented closures during the fire.
On December 10,
University of California, Santa Barbara
The University of California, Santa Barbara (UC Santa Barbara or UCSB) is a Public university, public Land-grant university, land-grant research university in Santa Barbara County, California, United States. Tracing its roots back to 1891 as an ...
cancelled classes, due to power outages and air quality concerns. The university also delayed its scheduled finals by a month. The expansion of the Thomas Fire also prompted more evacuation orders near Santa Barbara, with mandatory evacuation zones extending into Carpinteria and into the eastern outskirts of Santa Barbara.
Amtrak
The National Railroad Passenger Corporation, Trade name, doing business as Amtrak (; ), is the national Passenger train, passenger railroad company of the United States. It operates intercity rail service in 46 of the 48 contiguous United Stat ...
passenger rail service between Oxnard and San Luis Obispo on the
Pacific Surfliner
The ''Pacific Surfliner'' is a passenger train service serving the communities on the coast of Southern California between San Diego and San Luis Obispo.
The ''Pacific Surfliner'' is Amtrak's third-busiest service (exceeded in ridership only ...
was suspended indefinitely when the fire reached the
route along the Rincon north of Ventura.
Highways 150,
101, and
33 were partially shut down at various times due to the fire.
Officials began closing
State Highway 154 for several hours each morning in order to mobilize fire equipment on December 13.
On Tuesday, December 5, the city of Ventura issued a precautionary
boil-water advisory
A boil-water advisory (BWA), boil-water notice, boil-water warning, boil-water order, or boil order is a Public health, public-health advisory or directive issued by governmental or other health authorities to consumers when a community's drinkin ...
, because of the loss of pressure in the water system from power outages related to the fire.
A similar warning was issued by the
Casitas Municipal Water District which serves portions of the
Ojai Valley and communities along the Rincon Coast from Ventura to the
Santa Barbara County
Santa Barbara County, officially the County of Santa Barbara (), is a county located in Southern California. As of the 2020 United States census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa M ...
line.
The city of Ventura also issued a curfew as a result of the fire on Tuesday, which would be effective from 10 p.m. until 5 a.m. on the next morning, until further notice. The boil alert was lifted on December 12.
Environmental impacts
Air quality warnings were issued for many areas due to the fire, because of dangerous levels of smoke and particulates. During the alerts, authorities have recommended that people stay indoors, avoid driving in affected areas and drink plenty of fluids.
The east winds that have powered the fire have pushed much of the smoke out to sea or into areas somewhat distant from the fire. When the winds ease, the smoke has hung in the air in many communities. The typical moist, cool daily onshore winds in the evening have also been bringing smoke inland.
Native
chaparral
Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...
burned extensively to charred stems and ash.
Coastal chaparral is a
fire-adapted biome
A biome () is a distinct geographical region with specific climate, vegetation, and animal life. It consists of a biological community that has formed in response to its physical environment and regional climate. In 1935, Tansley added the ...
that burns frequently and catastrophically in
Santa Ana wind
The Santa Ana winds, occasionally referred to as the devil winds, are strong, extremely dry katabatic winds that originate inland and affect coastal Southern California and northern Baja California. They originate from cool, dry high-pressure a ...
. The chaparral plant species readily
re-sprout or regenerate from
serotinous
Serotiny in botany simply means 'following' or 'later'.
In the case of serotinous flowers, it means flowers which grow following the growth of leaves, or even more simply, flowering later in the season than is customary with allied species. Havi ...
seed in the
Mediterranean climate
A Mediterranean climate ( ), also called a dry summer climate, described by Köppen and Trewartha as ''Cs'', is a temperate climate type that occurs in the lower mid-latitudes (normally 30 to 44 north and south latitude). Such climates typic ...
of coastal, Southern
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
.
The Inter-agency Thomas Fire Command mapped at least 50
chaparral
Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...
fires of various sizes that had burned in the Thomas Fire area since 1950. The 1985 Wheeler Fire burned the central portion of the Thomas Fire.
Government response
In a radio interview, Neal Andrews explained how he was elected by the city council to serve as the new mayor, at the regular Monday night city council meeting in Ventura City Hall, about three hours after the fire broke out some away.
On Tuesday, December 5, 2017, at 10:45 p.m. PST, Governor
Jerry Brown
Edmund Gerald Brown Jr. (born April 7, 1938) is an American lawyer, author, and politician who served as the 34th and 39th governor of California from 1975 to 1983 and 2011 to 2019. A member of the Democratic Party (United States), Democratic P ...
declared a
state of emergency
A state of emergency is a situation in which a government is empowered to put through policies that it would normally not be permitted to do, for the safety and protection of its citizens. A government can declare such a state before, during, o ...
in Ventura County, due to the Thomas Fire. On his visit to Ventura on Saturday to survey the damage, Brown called the fires a "terrible tragedy for so many people."
Aftermath
Debris flows in Montecito
On January 9, 2018, 3:30 AM, PST, of
rain
Rain is a form of precipitation where water drop (liquid), droplets that have condensation, condensed from Water vapor#In Earth's atmosphere, atmospheric water vapor fall under gravity. Rain is a major component of the water cycle and is res ...
in 5 minutes was reported at
Montecito.
Heavy rain on burned hill slopes above the community resulted in rapid
erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
,
mud flow
A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/se ...
and
debris flow
Debris flows are geological phenomena in which water-laden masses of soil and fragmented Rock (geology), rock flow down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. ...
(
mass wasting
Mass wasting, also known as mass movement, is a general term for the movement of rock (geology), rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is no ...
) of soil and stream channels, causing catastrophic damage in Montecito Creek and San Ysidro Creek.
On January 21, 21 fatalities, 2 missing persons, 129 destroyed residences and 307 damaged residences, attributed to debris flows, were reported by the inter-agency, storm-response team
in Santa Barbara County.
Writer
T.C. Boyle, whose Montecito home was within the proximity of both the fire and mudslides, documented the collective trauma in
The New Yorker
''The New Yorker'' is an American magazine featuring journalism, commentary, criticism, essays, fiction, satire, cartoons, and poetry. It was founded on February 21, 1925, by Harold Ross and his wife Jane Grant, a reporter for ''The New York T ...
magazine.
[After the mudslides, an absence in Montecito](_blank)
, ''The New Yorker
''The New Yorker'' is an American magazine featuring journalism, commentary, criticism, essays, fiction, satire, cartoons, and poetry. It was founded on February 21, 1925, by Harold Ross and his wife Jane Grant, a reporter for ''The New York T ...
'', T.C. Boyle, January 22, 2018. Retrieved January 24, 2018
Debris flows are generated in the following general sequence of events: Fire reduces the organic
soil
Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
layer to ash and char. Water-repellent, organic
hydrocarbons
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic; their odor is usually faint, and may b ...
condense in shallow, mineral soil, enhancing
runoff. Locally
heavy rain, exceeding the
infiltration rate of the soil, generates
surface runoff
Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...
.
Eroded
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust and then transports it to another location where it is deposited. Erosion is disti ...
unconsolidated sediment and ash is
suspended and
dissolved, increasing the
density
Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...
of the flow.
Pore water pressure
Pore water pressure (sometimes abbreviated to pwp) refers to the pressure of groundwater held within a soil or Rock (geology), rock, in gaps between particles (soil pore, pores). Pore water pressures below the phreatic level of the groundwater are ...
developed in unconsolidated soil and sediment causes
liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics.
It occurs both naturally and artificially. As an example of t ...
.
Erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
increases as
gravity
In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...
drives
mud flow
A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/se ...
through the
drainage basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
in confined
channels
Channel, channels, channeling, etc., may refer to:
Geography
* Channel (geography), a landform consisting of the outline (banks) of the path of a narrow body of water.
Australia
* Channel Country, region of outback Australia in Queensland and pa ...
.
Mud flow
A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/se ...
s mobilize woody debris and larger sedimentary particles as
debris flow
Debris flows are geological phenomena in which water-laden masses of soil and fragmented Rock (geology), rock flow down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. ...
, which continues to accumulate as smaller channels combine with larger channels. As the size of the debris flow increases, larger particles are
entrained, channel
erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
occurs,
landslides
Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslide ...
and vegetation are incorporated. Multiple
debris flow
Debris flows are geological phenomena in which water-laden masses of soil and fragmented Rock (geology), rock flow down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. ...
s may be generated in the eroding, mountainous portion of the
drainage basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
. Debris flows typically surge, as
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...
rate and
sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
supply vary,
hydraulic jump
A hydraulic jump is a phenomenon in the science of hydraulics which is frequently observed in open channel flow such as rivers and spillways. When liquid at high velocity discharges into a zone of lower velocity, a rather abrupt rise occurs in ...
s occur,
landslide dam
A landslide dam or barrier lake is the natural damming of a river by some kind of landslide, such as a debris flow, rock avalanche or volcanic eruption. If the damming landslide is caused by an earthquake, it may also be called a quake lake. Some ...
s in the channel form and collapse. Upon exiting the steeper mountain
canyon
A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...
, as the
stream gradient
Stream gradient (or stream slope) is the grade (or slope) of a stream. It is measured by the ratio of drop in elevation and horizontal distance. It is a dimensionless quantity, usually expressed in units of meters per kilometer (m/km) or feet pe ...
is reduced, the
debris flow
Debris flows are geological phenomena in which water-laden masses of soil and fragmented Rock (geology), rock flow down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. ...
spreads laterally and begins to
deposit larger particles on the
alluvial fan
An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...
. Where the stream channel is plugged with debris, lateral channel migration occurs, building upon the existing
alluvial fan
An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...
deposits. Deposition also occurs down-stream of the alluvial fan, where
stream gradient
Stream gradient (or stream slope) is the grade (or slope) of a stream. It is measured by the ratio of drop in elevation and horizontal distance. It is a dimensionless quantity, usually expressed in units of meters per kilometer (m/km) or feet pe ...
decreases, on the
floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...
,
alluvial plain
An alluvial plain is a plain (an essentially flat landform) created by the deposition of sediment over a long period by one or more rivers coming from highland regions, from which alluvial soil forms. A ''floodplain'' is part of the process, bei ...
,
coastal plain
A coastal plain (also coastal plains, coastal lowland, coastal lowlands) is an area of flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and an upland area.
Formation
Coastal plains can f ...
and
river delta
A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creat ...
. As
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...
,
subsurface flow,
runoff,
stream flow and supply of
sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
and debris decreases, the stream reverts to low-flow characteristics. It takes years for disturbed channels to achieve relative
stability
Stability may refer to:
Mathematics
*Stability theory, the study of the stability of solutions to differential equations and dynamical systems
** Asymptotic stability
** Exponential stability
** Linear stability
**Lyapunov stability
** Marginal s ...
as
bed load
The term bed load or bedload describes particles in a flowing fluid (usually water) that are transported along the stream bed. Bed load is complementary to suspended load and wash load.
Bed load moves by rolling, sliding, and/or Saltation (geolo ...
sediment adjusts and vegetation is reestablished.
Recovery
A disaster relief center was set up to assist victims with interim and longer term living arrangements. Home owners could get help navigating the difficult and often confusing process of clearing the rubble at their home site and preparing to rebuild. The
Federal Emergency Management Agency
The Federal Emergency Management Agency (FEMA) is an agency of the United States Department of Homeland Security (DHS), initially created under President Jimmy Carter by Presidential Reorganization Plan No. 3 of 1978 and implemented by two Exec ...
(FEMA) partnered with state and local agencies to operate the center along with offering loans and assistance in getting medical prescriptions filled.
Clean up of materials like asbestos, pesticides, plastics, and electronic devices began almost immediately after the flames were out. The ruins of burned homes and vehicles can have a harmful impact on the surrounding environment.
]
Investigation
Soon after the Thomas Fire started, officials began to investigate the cause of the wildfire. The Thomas Fire originated as two separate fires, with the first fire igniting on December 4 at 6:26 p.m. PST, on a cattle ranch on Anlauf Canyon Road near
Thomas Aquinas College, while the second fire started about 30 minutes later, nearly north in Upper Ojai, at the top of Koenigstein Road. The newer fire quickly merged into the Thomas Fire later that night.
Residents on Koenigstein Road have said that a transformer exploded, but officials have not confirmed this claim.
In March 2019, investigators determined that Southern California Edison’s equipment had sparked both ignitions that became the Thomas Fire, but in a settlement with public agencies, the utility did not admit fault.
In September 2020, Edison announced a combined settlement of $1.16 billion with the insurance companies over the Thomas Fire and Montecito Mudslide.
On December 16, 2021 the
California Public Utilities Commission
The California Public Utilities Commission (CPUC or PUC) is a regulatory agency that regulates privately owned public utilities in the state of California, including electric power, telecommunications, natural gas and water companies. In addition ...
approved penalties and permanent disallowances against
Southern California Edison
Southern California Edison (SCE), the largest subsidiary of Edison International, is the primary electric utility company for much of Southern California. It provides 15 million people with electricity across a service territory of approximate ...
for violations related to the ignition of five 2017–2018
Southern California
Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...
wildfires. Under a proposed settlement with the CPUC’s Safety and Enforcement Division, SCE shareholders will pay a $110 million penalty to California’s General Fund, incur a $375 million permanent disallowance for cost recovery, and contribute $65 million in shareholder funds to safety measures, for a total of $550 million.
Growth and containment progress
See also
*
2017 California wildfires
In terms of property damage, 2017 was the most destructive wildfire season on record in California at the time, surpassed by only 2018 California wildfires, the 2018 season and 2020 California wildfires, the 2020 season, with a total of 9,560 f ...
**
October 2017 Northern California wildfires
The October 2017 Northern California wildfires, also known as the Northern California firestorm, North Bay Fires, and the Wine Country Fires were a series of 250 wildfires that started burning across the state of California, United States, ...
**
December 2017 Southern California wildfires
A series of 29 wildfires ignited across Southern California in December 2017. Six of the fires became significant wildfires, and led to widespread evacuations and property losses. The wildfires burned over , and caused traffic disruptions, scho ...
*
List of California wildfires
This is a partial and incomplete list of wildfires in the US state of California. California has dry, windy, and often hot weather conditions from spring through late autumn that can produce moderate to severe wildfires. Pre-1800, when the a ...
*
2018 Southern California mudflows
*
Tubbs Fire
The Tubbs Fire was a wildfire in Northern California during October 2017. At the time, the Tubbs Fire was the most destructive wildfire in California history, burning parts of Napa County, California, Napa, Sonoma County, California, Sonoma, a ...
*
October 2007 California wildfires
The October 2007 California wildfires, also known as the Fall 2007 California firestorm, were a series of about thirty wildfires (17 of which became major wildfires) that began igniting across Southern California on October 20. At least 1,500 h ...
*
Soberanes Fire
*
Carr Fire
The Carr Fire was a large wildfire in 2018 in Northern California's Shasta and Trinity counties. The fire ignited on July 23 and burned before it was fully contained on August 30. The Carr Fire destroyed 1,604 structures, including more tha ...
Notes
References
External links
Thomas Fire Ventura, CA
Thomas Fire information - InciWeb Incident Information System
Thomas Fire maps – InciWeb Incident Information System
Southern California Geographic Area Coordination CenterSee the destruction and fury of Ventura’s Thomas fire from space– Los Angeles Daily News
USGS Earth Explorer-
Landsat
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Lan ...
and
Sentinel-2
Sentinel-2 is an Earth observation mission from the Copernicus Programme that acquires optical imagery at high spatial resolution (10 m to 60 m) over land and coastal waters. The mission's Sentinel-2A and Sentinel-2B satellites were joined in or ...
satellite imagery
NASA Worldview-
MODIS
The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite-based sensor used for earth and climate measurements. There are two MODIS sensors in Earth orbit: one on board the Terra (EOS AM) satellite, launched by NASA in 19 ...
and
Suomi NPP
The Suomi National Polar-orbiting Partnership (Suomi NPP), previously known as the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) and NPP-Bridge, is a weather satellite operated by the United State ...
near real-time, medium resolution satellite imagery
SDSC WiFire Interactive Map– San Diego Supercomputer Center
Southern California's Worst Brush FiresDec 14 2017 a.m. Incident Update saved at archive.orgThomas Fire Aerial Photos 12/19– SBitZ.NET
Thomas Fire Aerial Photos 12/18– SBitZ.NET
Time lapse animations as seen from Santa Ynez Peak– HPWREN
*
{{California wildfires
2017 California wildfires
2018 California wildfires
December 2017 Southern California wildfires
Casitas Springs, California
December 2017 in the United States
Ojai, California
Santa Paula, California
Ventura, California
Wildfires in Santa Barbara County, California
Wildfires in Ventura County, California
Los Padres National Forest
Santa Ynez Mountains
Fillmore, California
Carpinteria, California
Montecito, California
Summerland, California
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