The 1991 Halloween blizzard was a powerful storm that caused a period of heavy

snowfall Snow consists of individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water througho ...

and

ice Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 ° C, 32 ° F, or 273.15 K. It occurs naturally on Earth, on other planets, in Oort cloud objects, and as interstellar ice. As a naturally oc ...

accumulation, which affected parts of the

Upper Midwest The Upper Midwest is a northern subregion of the U.S. Census Bureau's Midwestern United States. Although the exact boundaries are not uniformly agreed upon, the region is usually defined to include the states of Iowa, Michigan, Minnesota and Wi ...

of the United States, from October 31 to November 4, 1991. Over the last week of October 1991, a large storm system over the Atlantic Ocean (

1991 Perfect Storm The 1991 Perfect Storm, also known as The No-Name Storm (especially in the years immediately after it took place) and the Halloween Gale/Storm, was a damaging and deadly nor'easter in October 1991. Initially an extratropical cyclone, the storm a ...

) blocked most of the weather patterns over the eastern half of the United States, and in turn, moisture from the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

was funneled straight northward over the affected region. By the time the precipitation stopped falling, many cities in the eastern half of

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

and northwestern

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

had witnessed record early-season snowfall accumulations, while parts of southern Minnesota and northern

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

were crippled by a large ice storm.

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

air that was pulled southward behind the storm had combined with the heavy snow pack to produce many record low temperatures. Between the blizzard and the ice storm, 22 people were killed and over 100 were injured.

Meteorological synopsis

Surface map of the United States October 30 1991

The 1991 Halloween Blizzard developed from a strong arctic cold front that pushed south and east through the central United States several days prior. On October 28, temperatures to the east of the cold front were above normal. High temperatures reached into the 70s from the middle

Mississippi River Valley The Mississippi embayment is a physiographic feature in the south-central United States, part of the Mississippi Alluvial Plain. It is essentially a northward continuation of the fluvial sediments of the Mississippi River Delta to its conflue ...

south into northern Texas, and into the 80s across much of central and southern Texas. Meanwhile, high temperatures remained below

Fahrenheit The Fahrenheit scale () is a scale of temperature, temperature scale based on one proposed in 1724 by the German-Polish physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accou ...

across most of

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

and

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

. The contrast between the two air masses was stark, and by the morning of October 29 the cold front was about halfway through Texas. At 6 am CST, the temperature in the western Texas city of Amarillo had dropped to with a strong northerly breeze. Farther east in Texas, the temperature was 64 in Dallas – a 42-degree temperature difference over about . In the northern United States, morning lows were much colder. Temperatures were in the single digits across Montana and Wyoming and in the teens in

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

and

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

By October 30, the cold front had pushed east to the Texas shoreline with the

, and stalled in that location. As an upper-level

shortwave trough A shortwave or shortwave trough is an embedded kink in the trough / ridge pattern. Its length scale is much smaller than that of and is embedded within longwaves, which are responsible for the largest scale (synoptic scale) weather systems. Sho ...

approached the

Southern Plains The Great Plains is a broad expanse of flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include the mix ...

, it aided the development of an area of surface low pressure along the sharp temperature gradient near the Texas Gulf Coast. The development of low-pressure systems along coastal fronts in this fashion is relatively common in the cool season along the Texas Gulf Coast and along the Atlantic Seaboard near the

Gulf Stream The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude (North Carolin ...

current. From October 30 – 31, this low-pressure system slowly became better organized over Texas, before it ejected north over the

. This meridional trajectory of a low pressure track (almost due north from the western Gulf) is climatologically favorable to produce very heavy snowfall in the winter months because it allows copious amounts of moisture to flow north where it can interact with colder air. Cooler readings lingered at the very end of October across the

, and a re-enforcing pool of Arctic air was just beginning to push southeast through the western

Canadian Provinces Canada has ten provinces and three territories that are sub-national administrative divisions under the jurisdiction of the Canadian Constitution. In the 1867 Canadian Confederation, three provinces of British North America—New Brunswick, N ...

. On November 1, the low-pressure system moved north from western

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

into the

Upper Peninsula of Michigan The Upper Peninsula of Michigan—also known as Upper Michigan or colloquially the U.P. or Yoop—is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula of ...

and the minimum pressure fell about 24 millibars in 24 hours, indicative of rapid deepening and strengthening of the cyclone. The low pressure eventually became occluded, weakened, and then continued to dissipate as it pushed east across northern

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

in subsequent days.

Precipitation

The precipitation from this system began falling as snow in Iowa late on October 30, and by the morning of October 31, it had changed over to ice and spread northward across southeast Minnesota. During

Halloween Halloween, or Hallowe'en (less commonly known as Allhalloween, All Hallows' Eve, or All Saints' Eve), is a celebration geography of Halloween, observed in many countries on 31 October, the eve of the Western Christianity, Western Christian f ...

day, the precipitation spread to the north, where it fell mostly as rapidly accumulating snow. The snow continued to develop northward, eventually spreading into the Minnesota Arrowhead. Eventually all of the precipitation changed over to snow, and in some areas it would continue falling until November 4.

Snow

The heavy snow began falling across east central Minnesota and northwest Wisconsin during the late afternoon hours of October 31. By midnight, the

Twin Cities Twin cities are a special case of two neighboring cities or urban centres that grow into a single conurbation – or narrowly separated urban areas – over time. There are no formal criteria, but twin cities are generally comparable in stat ...

had already recorded 8.2 in (20.8 cm) of snow. This not only set a record for the largest amount of snow on that date, but also for the most snow ever recorded in the Twin Cities during the month of October. As the storm system pushed its way northward, more communities in eastern Minnesota and northwestern Wisconsin began to experience similar conditions; and

thundersnow Thundersnow, also known as a winter thunderstorm or a thundersnow storm, is a thunderstorm in which snow falls as the primary precipitation instead of rain. It is considered a rare phenomenon. It typically falls in regions of strong upward moti ...

occurred as far north as

Duluth Duluth ( ) is a Port, port city in the U.S. state of Minnesota and the county seat of St. Louis County, Minnesota, St. Louis County. Located on Lake Superior in Minnesota's Arrowhead Region, the city is a hub for cargo shipping. The population ...

. Over the next two days the snow continued to fall, leading to additional snowfall of one to two feet (30 cm to 60 cm). By the time the snowfall ended on November 4, the storm had dropped 36.9 in (93.7 cm) on Duluth, the largest single snow storm total in Minnesota history at that time. The

received 28.8 in (72.1 cm), setting a single-storm record for the metropolitan area. In all, at least one foot (30 cm) of snow fell in a swath approximately 100 mi (160 km) wide from south central Minnesota, northeastward into northwestern Wisconsin and into the Minnesota Arrowhead. A more narrow band of 2+ ft (60+ cm) of snow fell from the Twin Cities to Duluth and northward.

Ice

Areas of southern Minnesota and Iowa along and south of the

I-90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain states, Mountain West, Great Pla ...

corridor did not see as much snow, but instead saw a major

ice storm An ice storm, also known as a glaze event or a silver storm, is a type of winter storm characterized by freezing rain. The National Weather Service, U.S. National Weather Service defines an ice storm as a storm which results in the accumulatio ...

. Though the precipitation started out as snow in these areas, it changed over to ice during the day on October 31 and continued falling over the next day. Ice accumulations as high as 2–3 in (6 cm–9 cm) were recorded in these areas before the precipitation changed to snow. Up to 10 in (25.4 cm) of snow proceeded to fall on top of ice accumulations from the previous day, making travel even more treacherous. Up to 1 inch of ice accumulation was reported as far south as

Omaha, Nebraska Omaha ( ) is the List of cities in Nebraska, most populous city in the U.S. state of Nebraska. It is located in the Midwestern United States along the Missouri River, about north of the mouth of the Platte River. The nation's List of United S ...

Impact

Most of Minnesota, western Wisconsin and northern Iowa were heavily impacted by the storm. $63+ million in damages was reported from fallen power lines, and $5 million in crop damages were reported in Iowa. Eleven counties in southern Minnesota were declared federal disaster areas, and 52 counties in Iowa were declared disaster areas. At least 100,000 people lost power because of the weight of the ice downing power lines, and in some cases it took up to a week for the power to be restored. Many roads were closed both from the snow and ice, including long stretches of I-90, I-35 and I-29 in Iowa, Minnesota and South Dakota. Highway snow removal was hindered by record cold temperatures that followed the storm and transportation was hampered for many days. Nine hundred schools and business were closed in Minnesota alone. The storm occurred on a Thursday night. Schools in Minong, Wisconsin (40 miles southeast of Superior) were closed even the Monday following the storm. Twenty-two people died in this storm, twenty in Minnesota and two on the Mississippi River near La Crosse.

Records

In eastern Minnesota, the Halloween Blizzard shattered many of the previous October snowfall records. The 8 inches that fell in the Twin Cities on October 31 was more snow than had ever been recorded in any October in its recorded history. November 1 saw similar daily records fall, but with a more wide reaching area from most of central Minnesota eastward to

La Crosse La Crosse ( ) is a city in La Crosse County, Wisconsin, United States, and its county seat. Positioned alongside the Mississippi River, La Crosse is the largest city on Wisconsin's western border. La Crosse's population was 52,680 as of the 20 ...

and

Eau Claire, Wisconsin Eau Claire ( ; lit. "clear water") is a city in Eau Claire County, Wisconsin, Eau Claire and Chippewa County, Wisconsin, Chippewa counties in the U.S. state of Wisconsin. It is the county seat, seat of Eau Claire County. It is the List of citie ...

. Following the storm Arctic air poured southward from Canada to produce many record low temperatures in these same areas.

Bismarck, North Dakota Bismarck (; from 1872 to 1873: Edwinton) is the List of capitals in the United States, capital city of the U.S. state of North Dakota and the county seat, seat of Burleigh County, North Dakota, Burleigh County. It is the state's List of cities i ...

, sank to on October 31, breaking their previous record low of by 16 degrees. Record snow and cold was recorded as far south as Nebraska and Colorado.http://www.crh.noaa.gov/oax/?n=Halloween
/ref> The Arctic air also spread over Chicago, recording a low of 11 on November 4.http://www.crh.noaa.gov/dtx/climate/fnt_summary_2003.php
/ref> Four weeks later on November 29 – 30, another large storm system dropped as much as 18 inches of snow over these same areas. These two storms combined to set a single-month record for most snowfall in the Twin Cities and Duluth.

References

External links

Minnesota Public Radio – Jet Streaming for Wednesday, October 31, 2007 (MP3)
{{United States winter storms 1991-10 Halloween blizzard Halloween blizzard Halloween blizzard Halloween Halloween in the United States Halloween blizzard Halloween blizzard Halloween blizzard Halloween blizzard Halloween blizzard Halloween blizzard Halloween blizzard Halloween blizzard October 1991 in the United States November 1991 in the United States