National Snow and Ice

Northern Hemisphere Snow and Ice

The 2012/13 winter season (December 2012-February 2013) was warmer and wetter than average for the contiguous United States. December was warm (10^th warmest) and wet (20^th wettest) for the Lower-48, while January and February were both near average in terms of temperature and precipitation. Regionally, warmer-than-average temperatures during the three-month period were observed east of the Rockies, while the West had near- and below-average temperatures. In terms of precipitation, most locations east of the Rockies were also wetter than average, with the wettest locations being the Great Lakes and Southeast. The West Coast and Northern Rockies had below-average precipitation during the winter season. Several major winter storms did impact the central and eastern U.S. during the cold season of 2012/13 bringing with them significant snowfall, mostly during February and March, with two unusual late-season storms in April and May. However, snowfall and winter snowpack were below-average across the high elevations of California, the Great Basin, and the Southern Rockies. The low snowfall totals across California were a precursor to both the driest year on record in the state and the development of drought conditions during 2013.

Contiguous U.S. Winter Snow Cover Extent Anomalies
Data Source: Rutgers Global Snow Lab

According to data from the Rutgers Global Snow Lab, the winter snow cover extent was above average, while the spring snow cover extent was much above average. The satellite-derived snow cover extent for December 2012—February 2013 was approximately 1.3 million square miles, which was 127,000 square miles above the 1981-2010 average. This marked the 15^th largest seasonal snow cover extent in the 1966-present period of record. Despite a below-average May snow cover extent for the Lower-48, the above-average snow cover in March and April was enough for the spring (March-May) snow cover extent to be 130,090 square miles above the 1981-2010 average of 355,500 square miles and the eighth largest spring snow cover extent on record. The above-average spring snowfall in many locations exceeded the amount of snow that was observed during the preceding winter season. A select list of those locations is available here.

Western U.S. Snowpack
April 1, 2013
Source: USDA

Winter and spring mountain snowpack provide a crucial water source across much of the western United States. The total annual water budget for agriculture and human use in the mountainous West is highly dependant on the amount of snow melt that will occur in spring and is proportional to the amount of snow on the ground. The annual snowpack typically reaches its maximum value at the end of March. According to data from the USDA, on April 1^st, above-normal snowpack was observed across the Cascades of Oregon and Washington; near-normal snowpack was present for much of the Northern Rockies of Idaho and Montana; below and much below normal snowpack was observed for central and eastern Oregon, the Sierra Nevada Mountains, much of the Great Basin and in the Central and Southern Rockies. Locations in California, Nevada, Arizona, and New Mexico had snowpack totals less than 25 percent of normal. In Alaska, much of the state had near-normal snowpack with the exception of northwestern and southwestern areas of the state. Snowpack totals greater than 130 percent of normal were reported along the Alaskan panhandle. By May 1^st, the snowpack totals across the Sierra Nevada Mountains and the Southern Rockies were less than 25 percent of normal.

Select Significant Events

Satellite Image of Northeast Snowcover 10 February
Source: NOAA's Environmental Visualization Lab

A Nor'easter hit the East Coast on February 7^th-10^th dropping heavy snowfall from New Jersey to Maine. The storm was rated a Category 3 on a scale from 1 to 5 on NOAA's Northeast Snowfall Impact Scale (NESIS), which takes into account snowfall in populated areas to understand societal impact. A Category 3 denotes a "major" winter storm for the region. This was the most significant snow storm to hit the region since February 2010. The footprint of heavy snow was relatively small when compared to other Nor'easters, but the heavy snowfall in the densely populated New York City and Boston metro areas led to a high NESIS value. Hamden, Connecticut had the highest reported snowfall total with 40.0 inches. The 21.8 inches at Boston's Logan Airport was the sixth largest single storm total on record for the city. In Portland, Maine, 31.9 inches of snow fell, and according to the National Weather Service, was the largest storm total for the city. Other impacts from the storm included strong winds and storm surge. Wind gusts in excess of 80 mph led to blizzard conditions for many locations. The storm caused significant storm surge along the Massachusetts coast, but since the storm hit at low tide coastal flooding was only a minor issue.

RSI for 20-23 Feb. snow storm

The first of back-to-back major winter storms impacted the Central Plains, parts of the Ohio Valley, and Upper Midwest states on February 20^th-23^rd. The storm was the result of a powerful low pressure system that emerged from the Southern Rockies, dropping heavy snow from New Mexico to Michigan. The heaviest snowfall was centered on Kansas, with a large portion of the state receiving over a foot of snow. Wichita, Kansas received 14.2 inches of snow, marking the second largest single-storm snowfall total for the city, behind a 1962 storm when 15.0 inches of snow was observed. Russell, Kansas received 22.0 inches of snow from the event. In the South Climate Region, the storm ranked as a Category 4 on the Regional Snowfall Impact (RSI) scale, a regional variant of the NESIS. This marked the 10^th most significant winter storm on record for the region. Despite numerous negative impacts, the precipitation was a welcome sight for many as it provided some drought relief in the region.

The second of the two major winter storms to hit the central U.S. occurred on February 25^th-28^th. Heavy snowfall was once again reported from New Mexico to Michigan, but the heaviest snowfall totals were displaced farther south compared to the previous storm. The northern Texas panhandle and western Oklahoma bore the brunt of the heavy snow and wind. Wichita, Kansas, received an additional 6.8 inches of snow, contributing to a monthly total of 21.2 inches of snow for the city — the most on record for any month. The previous snowiest month was February 1913 when 20.5 inches of snow was observed. Blizzard conditions were reported in the Texas Panhandle and western Oklahoma for several hours, with visibilities reduced to less than 50 feet. Numerous roads, including interstate highways 40 and 27, were closed for several hours as crews were not able to keep roads clear due to the rapid rate of snowfall. Amarillo, Texas, received 19.0 inches of snow with winds of 75 miles per hour. Numerous snow records were broken or nearly broken for Amarillo — this was the third largest snow event for the city, the second largest calendar day snowfall of any date, and the largest single day snowfall during the month of February. The strong winds and heavy snow resulted in snow drifts exceeding 10 feet in height. This storm also provided some drought relief to the areas where snow was observed.

4-9 March 2013 NESIS

A late-season snow storm moved from the Northern Plains to the Mid-Atlantic on March 4^th-9^th bringing snowfall from the Dakotas to East Coast. The storm originated as a fast-moving low pressure system from Canada, often referred to as a 'clipper'. The storm intensified into a Nor'easter as it moved off the East Coast. Locations in the Central Appalachians of the Virginias, as well as parts of New England, received over 20 inches of snowfall from the storm. Locations in seventeen states received at least 6 inches of snow. The storm also caused coastal flooding and erosion from Delaware to Maine as it moved along the coast. The large size of the storm, combined with strong winds, caused water to pile up along coastal regions resulting in high water levels. Several structures along the waterfront were lost in Massachusetts. The storm was rated a Category 2 ("Significant") storm on the Northeast Snowfall Impact Scale (NESIS).

13-15 April North Dakota Snowfall

A very active storm pattern, from the Central Rockies through the Northern Plains and into the Midwest, in combination with colder-than-average conditions, resulted in record snowfall totals during April. The two largest storms hit on April 9^th-12^th and April 13^th-15^th. The first storm system dropped heavy snowfall from Colorado to South Dakota. Rapid City, South Dakota received 22.4 inches of snow — the second most for any April storm in that city — and the 15 inches that fell on the 9^th was the third highest single-day snowfall on record for the city. Areas just west of Denver, Colorado received nearly 2 feet of snow, and hundreds of flights were cancelled at Denver International Airport. The second storm, on the 13^th-15^th, hit the Northern Plains. In Bismarck, North Dakota 17.3 inches of snow fell on the 14^th, breaking the record for most snowfall on any calendar day. All 350 miles of Interstate 94 passing through North Dakota were closed, as well as a large portion of the same highway in Minnesota.

Select April snow records

• Duluth, Minnesota: April snow total of 50.8 inches marked snowiest month of any month on record.
• Rapid City, South Dakota: April snow total of 43.1 inches marked snowiest month of any month on record.
• Pierre, South Dakota: April snow total of 20.8 inches, most on record for April.
• Twin Cities, Minnesota: April snow total of 17.9 inches marked 3^rd snowiest April on record.
• Fargo, North Dakota: April snowfall total of 16.7 inches was the most monthly snowfall this winter season and 4^th snowiest April on record.
• Bismarck, North Dakota:
  • April 14^th snowfall (17.3 inches) record snowfall for any date.
  • April 2013 monthly snowfall of 21.8 inches marked snowiest April on record.

1-3 May Upper Midwest Snowfall
Source: National Weather Service

A strong storm brought late-season snowfall on May 1^st-3^rd from the Rockies, through the Central Plains, and into the Mississippi River Valley. Locations as far south as Arkansas received measureable snowfall. Ahead of the storm system, temperatures surged into the mid and upper 80s in the Upper Midwest. Behind the system, cold Arctic air filtered into the central United States, allowing precipitation to fall mostly as snow. The cold, Arctic air broke temperature records for this late in the spring season. Denver, Colorado dipped to 19°F on May 2^nd, tying the record coldest temperature observed during the month of May. The highest snowfall totals occurred across the Rockies and the Upper Midwest, where snowfall exceeded 20 inches in parts of Colorado and Wyoming as well as northern Wisconsin. Many locations in the storm's track broke daily, 2-day, and monthly snowfall totals during the event.

Select snowfall records from the May 1^st – 3^rd, based on preliminary data from the National Weather Service:

• Eau Claire, WI: 2-day snowfall of 9.3 inches on May 2^nd – 3^rd. This broke the 2-day snowfall record for May and exceeded the monthly average snowfall for the city.
• Decatur, AR: Storm total of 5.0 inches of snow. First snow ever observed in Arkansas during month of May and latest snowfall on record for the state.
• St. Cloud, MN: 2-day snowfall of 3.3 inches on May 2^nd – 3^rd was a record 2-day May snowfall.
• Omaha, NE: 2-day snowfall of 3.1 inches on May 1^st–2^nd was a record 2-day May snowfall and record monthly snowfall total.
• Lincoln, NE: 2-day snowfall of 2.7 inches on May 1 ^st–2^nd was the second largest May snow event.
• Osage, IA: Storm total snowfall of 13.0 inches. Highest May snowfall total for Iowa and first May snow storm to produce more than one foot of snow in the state.
• Des Moines, IA: Storm total snowfall of 6.9 inches was the largest May snowfall and a monthly record snowfall.
• Kansas City, MO: Trace of snow on May 3^rd was the latest date of observed snowfall in city.
• Tulsa, OK: Trace of snow on May 2^nd was the latest date of observed snowfall and first snow observed in May.
• Rochester, MN: Storm total snowfall of 7 inches marked the largest May snowstorm for the city.
• Twin Cities, MN: 0.5 inch accumulated on May 3^rd, the 8^th highest daily snowfall for month of May.
• Topeka, KS: Trace snowfall on May 2^nd, only 3^rd occurrence of May snowfall.

Early October Storm Snowfall Totals

On October 3^rd–5^th, an early-season blizzard hit the Northern Rockies and Plains, dropping up to three feet of snow in some locations. Wind gusts over 70 miles per hour were also reported, with 25,000 homes losing power. The Black Hills Regions of South Dakota received the heaviest snowfall. During the three-day event, Rapid City received 23.1 inches of snow, breaking the maximum 1-day snowfall total for the month of October, the October monthly snowfall record (previous record was 15.1 inches in 1919), and ranked as the second highest 3-day snowfall total for any month, behind the 25.6 inches that fell in April 1927. Casper, Wyoming received 16.2 inches of snow during the event, ranking as the 10^th highest single-storm snowfall on record for the city and the most snowfall this early in the season. The largest impact from the storm was the loss of cattle. An estimated 20,000 head of cattle died during the storm. This early in the season, most cattle had not yet grown thick winter coats, making them susceptible to the cold, snow, and wind. The cattle loss accounted for approximately 15 to 20 percent of South Dakota's entire cattle population. Warm and rainy conditions after the blizzard led to rapid snow melt, complicating the cleanup with fields and roads covered in mud. The storm received an initial rating of a Category 3, or Major Winter Storm, on the Regional Snowfall Impact (RSI) scale for the Northern Rockies and Plains region.