NOAA's National Centers for Environmental Information
The two satellite-derived images above show the daily snow cover across North America (left map) and the Northern Hemisphere (right map) throughout December 2008. The maps help illustrate the snow coverage expanding southward from the Canadian Provinces into the U.S. By the end of December, 37.9 percent of the country was covered by snow compared to 26.8 percent one month prior. Based on a NOAA-supported analysis by Rutgers University climatologists of NOAA satellite observations of snow cover extent, 6.8 million square miles (17.6 million square kilometers) of North America were covered by snow in December 2008, which is 0.4 million square miles (1.0 million square kilometers) above the 1966-2008 average. It was the seventh largest extent of snow cover for North America compared with 42 previous Decembers.
During the month of December more than 2,000 daily snowfall records were broken across the U.S. The record snowfalls were the result of several winter storms that wreaked havoc along the western seaboard and across the Plains, Great Lakes and the Northeast. The more noteworthy snow events took place in the Desert Southwest, the Upper Midwest, the Northeast, southeast Texas, and southwestern Louisiana.
On December 11th, southwest Louisiana and southeast Texas experienced a rare accumulating snowfall. The event was caused by an upper level low pressure system that interacted with widespread rainfall lingering from a previous event. The snow lasted for a few hours and was accompanied by thunder and lightning. Snow totals ranged from a trace up to six inches. On the following day in the Northeast, the same storm coated trees and wires with ice, causing an estimated 1.4 million customers to lose power. The damage from the storm was so severe that President Bush declared a state of emergency across much of the New England area. It was reported that at least 2 deaths were a direct result of the storm.
On December 17th, the mountains of Southern California saw as much as 30 inches of snow while the Las Vegas, Nevada airport reported a new daily record of 3.6 inches. It was the most snow for Las Vegas during any month since 7.5 inches fell in January 1979. More than 200 daily snowfall records were set on the 17th. Most of these records were located in the states of Iowa, Illinois, Kansas and Missouri. The active weather pattern allowed for strong weather systems to continuously track across the middle of the country, where record snow events began to occur on an every-other-day basis. More than 200 additional records were set on the 18th and 19th, when the same system that brought snow to Las Vegas moved northeast into the Great Plains. The snow totals from this system were generally in the range of six to ten inches.
These continuous snowfall events during December broke historical monthly records in many locations across the Upper Midwest. La Crosse, Wisconsin had their snowiest December on record as 32.7 inches fell. This also ranked as their fourth snowiest month on record. A December record of 45.6 inches of snow fell in Green Bay, Wisconsin, topping their previous record of 36.4 inches which was set in 1887. Madison, Wisconsin also experienced their snowiest December on record with 40.4 inches. Several locations in North Dakota received record amounts of snow in December, some of which were all-time monthly records. In Bismarck, the National Weather Service office recorded an all-time monthly snowfall record of 33.3 inches. Grand Forks received a record 30.1 inches of snow for the month, which was also their second snowiest month on record. Fargo also recorded an all-time record snowfall amount in any month with 33.5 inches. Additional events in the Upper Midwest brought the December snowfall totals to over 60 inches in some areas.
In the northwestern U.S., Portland, Oregon experienced their snowiest December with 18.9 inches recorded at the airport. This monthly total was their second snowiest month ever on record, bested only by the 41 inches that fell in January 1950. Spokane, Washington also set a December record with 46.2 inches of snow. The old record of 42.7 inches was set in 1996. To view additional records for the month, please visit NCDC's U.S. Records page.