NOAA's National Centers for Environmental Information
NH Snow Cover Extent
| April 2013 | Snow Cover Extent | Anomaly 1991-2020 | Trend per decade | Rank (47 years) | Record | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | million km² | million mi² | million km² | million mi² | Year(s) | million km² | million mi² | |||
| Northern Hemisphere | 32.59 | 12.58 | +2.66 | +1.03 | -0.47 | -0.18 | Largest | 9th | 1979 | 34.61 | 13.36 |
| Smallest | 39th | 1968 | 28.00 | 10.81 | |||||||
| North America | 14.81 | 5.72 | +1.64 | +0.63 | -0.14 | -0.05 | Largest | 3rd | 1975 | 15.08 | 5.82 |
| Smallest | 45th | 2010 | 11.02 | 4.25 | |||||||
| Eurasia | 17.78 | 6.86 | +1.02 | +0.39 | -0.34 | -0.13 | Largest | 18th | 1981 | 20.69 | 7.99 |
| Smallest | 30th | 2008 | 15.03 | 5.80 | |||||||
Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1967–2013 (47 years)
The Northern Hemisphere snow cover extent (SCE) during April 2013 was 32.20 million square km (12.43 million square miles), 2.14 million square km (830,000 square miles) above the 1981-2010 average. This was the 9th largest April SCE on record and the largest since 1996. Both the North American and Eurasian land areas had an above-average April SCE. Northern Hemisphere SCE is decreasing at an average rate of 540,000 square km (210,000 square miles) per decade.
During April, the North American SCE was much above average and ranked as the third largest April SCE on record. The monthly SCE was 14.75 million square km (5.69 million square miles), 1.75 million square km (670,000 square miles) above the 1981-2010 average. Only 1975 and 1982 had larger April SCE for North America. Canada experienced its second largest April SCE, while the contiguous U.S. had its fifth largest. Above-average snow cover was observed across most of Canada and the north-central United States. Below-average snow cover was present for the western U.S. and the Great Lakes Region. In the long term, April SCE across North America is decreasing at a rate of 140,000 square km (50,000 square miles) per decade.
Eurasian SCE was 17.45 million square km (6.74 million square miles), 400,000 square km (150,000 square miles) above the 1981-2010 average, and the 19th largest April SCE on record. Above-average snow cover was observed in Scandinavia, Eastern Europe, and northwestern China. Below-average snow cover was observed in southern Europe, Turkey, and much of central Asia. April SCE in Eurasia is decreasing at a rate of 410,000 square km (160,000 square miles) per decade.
Sea Ice Extent
| April 2013 | Sea Ice Extent | Anomaly 1991-2020 | Trend per decade | Rank (35 years) | Record | ||||
|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | Year(s) | million km² | million mi² | |||||
| Northern Hemisphere | 14.30 | 5.52 | -0.14% | -2.30% | Largest | 28th | 1982 | 15.47 | 5.97 |
| Smallest | 8th | 2007 | 13.85 | 5.35 | |||||
| Ties: 2002 | |||||||||
| Southern Hemisphere | 7.62 | 2.94 | +9.64% | +2.73% | Largest | 4th | 2008 | 8.24 | 3.18 |
| Smallest | 32nd | 1980 | 5.40 | 2.08 | |||||
| Globe | 21.92 | 8.46 | +3.06% | -0.66% | Largest | 9th | 1982 | 23.19 | 8.95 |
| Smallest | 27th | 2006 | 19.92 | 7.69 | |||||
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2013 (35 years)
According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for April 2013 was 14.37 million square km (5.55 million square miles), 2.60 percent below the 1981-2010 average, and the seventh smallest April sea ice extent on record. April Arctic sea ice extent is decreasing at an average rate of 2.4 percent per decade. The Arctic lost 1.5 million square km (444,000 square miles) of sea ice during April which is slightly higher than average for the month. Below-average ice extent was observed in the Barents Sea and the Sea of Okhotsk, while above-average ice was present in the Bering Sea.
The April 2013 Southern Hemisphere sea ice extent was 8.07 million square km (3.12 million square miles), 9.06 percent above the 1981-2010 average. This was the 5th largest April Antarctic sea ice extent on record. April Southern Hemisphere sea ice extent is increasing at an average rate of 2.6 percent per decade with substantial interannual variability.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.