National Snow & Ice - February 2011
The weather pattern during the first half of February brought two large snow storms to the central parts of the U.S., but a pattern change around the middle of the month shifted the storm track to the West coast and along the northern tier of the country. The snow broke many daily, monthly, and seasonal snowfall records at many locations within these regions. See our records page for additonal information. By the end of the month, most high elevation locations in the West had snow pack levels which were near- to above normal, with the exception of the southern Rockies and parts of the Cascade Mountains. February provided a reprieve from the snow for the Southeast and much of the Eastern Seaboard. Even though snowfall was widespread during February, a significant portion of the county continued to suffer from an ongoing drought. See the U.S. drought monitor for more information. According to data from the Rutgers Global Snow Lab, a NOAA supported facility, during the month, the Southeast, Mid-Atlantic, the Central Plains, and parts of the interior West had below average snow cover during the month. Conversely, the Great Lakes, the Northern Plains, and the high elevations of the West had above average snow cover.
Based upon satellite analysis, the contiguous U.S. had a February average snow cover extent 251,000 square miles (0.65 million square km) above the long-term average of 1.2 million square miles (3.1 million square km), ranking as the ninth largest February snow cover extent in the 45-year period of record. At the beginning of the month, 52.2 percent of the country was under snow cover — the Northeast, Great Lakes, the Central and Northern Plains, parts of the Southern Plains, and the high terrain of the West. By the end of the month, 49.5 percent of the U.S. was snow covered, the Northeast, Great Lakes, the Northern Plains, the high elevations of the West, and the Great Basin. The maximum monthly snow cover extent occurred on February 10th, when 65 percent of the U.S. was snow covered — all states except Florida had snow on the ground.
Water Vapor Imagery of 1 February Storm
On February 1st–3rd a large and powerful winter storm, dubbed the ‘Groundhog Day Blizzard’, hit the central and northern regions of the United States from New Mexico northward to Wisconsin, and eastward to New England. The storm stretched for thousands of miles, leaving behind at least five inches (12.7 cm) of snow in 22 states. The multi-faceted storm also brought an inch of ice to portions of the Ohio River Valley. Winds gusting upwards of 70 mph (113 km/hr) created widespread blizzard conditions, and snow drifts were reported as high as 10 feet (3 meters). Numerous highways were forced to close and thousands of flights were cancelled nationwide. The storm began across the Southern Plains on the 1st, where it dropped 1 to 2 feet (30.5 cm – 61 cm) of snow across Texas, Oklahoma, and Missouri. The largest snow amounts occurred across northern Illinois and southern Wisconsin on the 2nd. At Chicago, O’Hare Airport, the 20.2 inches (51.3 cm) of snow was the third largest storm accumulation ever recorded for the city. Racine, Wisconsin observed 26 inches (66.0 cm) of snow during the event, breaking the city’s 48-hour and 72-hour snowfall records. Snowfall records for Chicago date back to 1886 and to 1896 for Racine. The storm then moved off into the Northeast on the 3rd, where it left behind a foot of snow. Buildings in Connecticut and Massachusetts collapsed under the weight of the new snow, in addition to snow from previous storms. According to scientists at the CPC, the track of the storm was likely influenced by the ongoing La Niña across the equatorial Pacific. Please see Global Hazards for additional information on this storm.
10 February Oklahoma Temperature Records
On the 8th and 9th of the month, another powerful winter storm hit the Southern Plains states, leaving behind 20 inches (50.8 cm) or more of snow in Oklahoma, Arkansas, and Kansas. As the storm moved off to the east, it also brought snowfall to northern parts of the Gulf Coast States, with up to six inches (15.2 cm) of snow reported in parts of Mississippi and Alabama. Tulsa, Oklahoma, received 5.5 inches (14 cm) of snow for the event, helping push the city over its seasonal snowfall record, with 26.1 total inches (10.3 cm) accumulating since December. Records for Tulsa date back to 1893. Oklahoma, City received six inches (15.2 cm) of snow during the event, putting the monthly total to 18.9 inches (48 cm), marking the second snowiest month on record for Oklahoma City, behind March 1923 when 20.7 inches (52.6 cm) of snow fell. Spavinaw, Oklahoma received 27 inches (68.6 cm) of snow over a 24-hour period on the 8th and 9th, breaking the 24-hour snowfall record for the state. Also associated with the storm were very cold temperatures, once the associated cold front pass through. On the 10th, the temperature in Nowata, Oklahoma dropped to -31 degrees F (-35 degrees C), breaking the all-time coldest temperature record for the state of Oklahoma. Please see the Febuary Global Hazards report for more information on this storm.
22 February Minnesota Snow Accumulations
On February 20th and 21st, a snow storm moved through the Northern Plains and Western Great Lakes leaving behind up to 20 inches (50.8 cm) of snow. Minneapolis, Minnesota received 13.8 inches (35.1 cm) for the event, the largest February storm accumulation to affect the city on record, and the first time over a foot of snow has fallen in the city during the month of February. The previous record was 11.2 inches (28.4 cm) in February 2004. The entire winter season for Minneapolis has been particularly snowy, with snow during the December through February period measuring 66.7 inches (169.4 cm), the second snowiest on record, behind the same period in 1966-1967 when 71.7 inches (182.1 cm) of snow fell. Heavy snow during February is uncommon in the region, with the heaviest snows tending to occur earlier or later in the winter season. The copious amounts of snow this winter across the Northern Plains will likely cause issues this spring when it begins to melt into rivers, potentially causing flooding. According to NOAA scientist, there is an above average chance for record flooding in the region.
27 February Southern California Snow Cover
A strong and unseasonably cold storm system hit the West coast on February 24th through 27th, bringing a mixed bag of precipitation from Seattle to the suburbs of Los Angeles. As the cold front associated with the storm moved through it brought heavy rain and strong winds. Once it passed, cold air and Pacific moisture filtered into the region. Snow levels dropped to sea level, allowing snow to fall in downtown Seattle as well as the San Francisco airport, where a trace was measured. The last measureable snowfall greater than a trace in San Francisco was in 1976. In the Cascades and Sierra Nevada mountain ranges, snowfall totals reached up to four feet (122 cm) where the temperatures remained cool enough to support snow during the entire event. Further to the south, snow fell in the mountains around Los Angeles and San Diego, with snow levels dropping to around 1,000 feet (305 m).