National Snow & Ice - October 2011
NCDC added Alaska climate divisions to its nClimDiv dataset on Friday, March 6, 2015, coincident with the release of the February 2015 monthly monitoring report. For more information on this data, please visit the Alaska Climate Divisions FAQ.
October marks the beginning of the cold season for the United States, and snow typically begins to fall across the Northern tier of the country and the high terrain of the West. When weather conditions are averaged for the month of October 2011, most of the West had near- to above-normal precipitation. The Northeast also had above-average precipitation during the month, while the Mississippi River Valley and the central Gulf Coast had below-average precipitation. Temperatures were warmer than average across the Northern tier of the country and parts of the West, while below-normal temperatures were dominate across the Southeast. The warm temperatures across the West were associated with below-normal snow cover across the high terrain, during October.
An early October snow storm brought heavy snowfall to the Central Rockies between October 7th and 9th, but most accumulating snow fell across high elevations and had limited impacts. A late October storm between the 26th and 31st brought heavy snowfall amounts to the Front Range of the Rockies to northern Texas. The storm system then moved across the central parts of the country and into the Mid-Atlantic and Northeast where it brought snowfall from North Carolina to Maine. According to the Rutgers Global Snow Lab, a NOAA supported facility, the average snow extent across the contiguous United States for October 2011 ranked as 22nd smallest (23rd largest) in the 44-year satellite record at 38,225 square miles (99,000 square km) — 19,700 square miles (51,000 square km) below the long term average of 57,900 square miles (150,000 square km). At the beginning of the month, only the highest mountain peaks across the Pacific Northwest and Northern Rockies had snow cover, amounting to less than 0.01 percent of the contiguous United States. By the 31st, the area covered by snow increased to 6.6 percent, with snow on the ground across the Northern Rockies, the High Plains of Colorado and across most of the Northeast corridor.
Summary of Notable Snow Events:
Satellite image of Northeast Snowfall 30 Oct. 2011
A potent early season extra-tropical cyclone moved from the Rocky Mountains, across the U.S., into the Northeast between October 26th and 31st. The storm brought heavy snowfall across the Front Range and High Plains of Colorado. Snowfall amounts of over a foot were widespread across the region, and Ward, Colorado, received 19 inches (48.3 cm) of accumulation. The snowfall occurred two days after record high temperatures in the 70s °F and 80s °F were observed across the region. On October 28th, the storm moved eastward into the Plains, where it brought several inches of snowfall to the Texas Northern Panhandle. A new daily record of 3.1 inches (7.9 cm) of snow fell in Amarillo. The storm traversed the center of the country, where the predominate type of precipitation was rain. Between October 29th and 31st, the storm moved off the Atlantic Coast and rapidly intensified into a Nor’easter, and the northern side of the storm was cool enough to dump over a foot of snow over interior regions of the northeast. Snow was seen as far south as North Carolina. Over 30 inches of snow were reported across western Massachusetts and southern New Hamsphire. In Concord, Maine, 22.5 inches (57.2 cm) of snow accumulated between 3pm on the 29th and 7am on the 30th, setting the second greatest 24-hour snowfall on record for the city. Dozens of locations from Virginia to Maine set daily snowfall records on October 29th and 31st, as well as snowfall records for the month of October. The storm also broke the record at many locations for the most snowfall this early in the winter season. New York’s Central Park recorded 2.9 inches (7.4 cm) of snowfall during the storm — the first time since records began in 1869 that an inch or more of snowfall has been recorded during the month of October. The storm was preliminarily scored as a Category 1 (Notable) snow storm on the Northeast Snowfall Impact Scale (NESIS), which takes into account snowfall in populated areas of the Northeast. This is the first October snow storm to have significant enough impacts to be ranked on the NESIS. Significant damage was reported across the region from the storm because of the strong winds and many of the trees had not yet lost their foliage — the excess snow accumulating on branches caused them to break. The storm temperatures were also relatively warm, leading to a high water content of the snow (heavier snow). According to media reports, over 3 million people lost electricity and there were 22 storm-related fatalities.