The SCU (Santa Clara Unit) Lightning Complex fires were

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 ...

s that burned in the

Diablo Range The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. It stretches from the eastern San Francisco Bay Area at its northern end to the Salinas Valley a ...

in California in August and September 2020 as part of the

2020 California wildfire season 2020 was a record-setting year for wildfires in California. Over the course of the year, 8,648 fires burned , more than four percent of the state's roughly 100 million acres of land, making 2020 the largest wildfire season recorded in Calif ...

. The fire complex consisted of fires in Santa Clara,

Alameda An alameda is a street or path lined with trees () and may refer to: Places Canada * Alameda, Saskatchewan, town in Saskatchewan ** Grant Devine Dam, formerly ''Alameda Dam'', a dam and reservoir in southern Saskatchewan Chile * Alameda (Santi ...

, Contra Costa, San Joaquin,

Merced Merced (; Spanish language, Spanish for "Mercy") is a city in, and the county seat of, Merced County, California, United States, in the San Joaquin Valley. As of the 2020 United States census, 2020 census, the city had a population of 86,333, up ...

, and Stanislaus counties. The name is derived from the three-letter designation given to the

California Department of Forestry and Fire Protection The California Department of Forestry and Fire Protection, colloquially known as CAL FIRE, is the fire department of the California Natural Resources Agency in the U.S. state of California. It is responsible for fire protection in various area ...

(Cal Fire) division responsible for the Santa Clara, Alameda, Contra Costa, and parts of San Joaquin and Stanislaus counties, and the complex consisted of several distinct fires occurring in this region. The complex fire burned a total of from August 16 to October 1, 2020, making it the fifth-largest overall wildfire recorded in California's modern history, surpassed only by the 2018

Mendocino Complex Fire The Mendocino Complex Fire was a large complex of wildfires that burned in northern California for more than three months in 2018. It consisted of two wildfires, the River Fire and Ranch Fire, which burned in Mendocino, Lake, Colusa, and ...

, the 2021 Dixie Fire, the 2024

Park Fire The Park Fire was an extremely large wildfire in Northern California's Butte and Tehama counties. It ignited on July 24, 2024 in an alleged act of arson in the city of Chico's Bidwell Park in Butte County. Defying initial fire suppression ef ...

, and the 2020 August Complex fire. The SCU Complex was one of several fire complexes burning during August and September in California, most notably the LNU, CZU, and

August August is the eighth month of the year in the Julian and Gregorian calendars. Its length is 31 days. In the Southern Hemisphere, August is the seasonal equivalent of February in the Northern Hemisphere. In the Northern Hemisphere, August ...

complexes.

Progression

The fire complex started on August 16, 2020. It consisted of three zones: the Deer Zone in

Contra Costa County Contra Costa County (; ''Contra Costa'', Spanish language, Spanish for 'Opposite Coast') is a U.S. county, county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States census, the ...

; the Canyon Zone in

, Santa Clara and parts of Stanislaus counties; and the Calaveras zone in parts of Stanislaus, San Joaquin and

counties. On August 20, the fires reached

Lick Observatory The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton (California), Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The ...

, an astronomical telescopic

observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Th ...

operated by the

University of California The University of California (UC) is a public university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...

, located on Mount Hamilton. One residential building not in use was destroyed, and some other residential buildings were damaged, but the telescope domes themselves did not burn. By August 26, the Deer zone was fully contained, and the other Canyon and Calaveras zones had grown together into a single branch of the fire. On October 1, Cal Fire reported that the entire fire complex had been fully contained.

Effects

Casualties and property damage

The fire complex had destroyed 222 structures, damaged another 26, and injured 6 people. No fatalities were recorded.

Land ecology

A year following the fire the East Bay Regional Park District (EBRPD) and Save Mount Diablo (SMD) monitored the fire impact on the 6,000 acres of the park district lands. Their observation was that the burn was mostly beneficial for the ecology of the region, despite its extent. This was attributed to the fire's moderate to low intensity which spared most of the park trees, rejuvenated vegetation and triggered germination of rare species of fire poppies. The study prompted CalFire officials to consider increasing the use of prescribed burning in Alameda and Contra Costa counties.

References