NOAA's National Centers for Environmental Information
NH Snow Cover Extent
| December 2015 | Snow Cover Extent | Anomaly 1991-2020 | Trend per decade | Rank (50 years) | Record | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | million km² | million mi² | million km² | million mi² | Year(s) | million km² | million mi² | |||
| Northern Hemisphere | 43.48 | 16.79 | -0.79 | -0.31 | +0.38 | +0.15 | Largest | 32nd | 2012 | 46.85 | 18.09 |
| Smallest | 19th | 1980 | 37.44 | 14.46 | |||||||
| North America | 16.83 | 6.50 | -0.07 | -0.03 | +0.11 | +0.04 | Largest | 22nd | 2009 | 18.27 | 7.05 |
| Smallest | 29th | 1980 | 14.56 | 5.62 | |||||||
| Eurasia | 26.65 | 10.29 | -0.71 | -0.27 | +0.27 | +0.10 | Largest | 30th | 2002 | 29.70 | 11.47 |
| Smallest | 21st | 1980 | 22.88 | 8.83 | |||||||
Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1966–2015 (50 years)
The Northern Hemisphere snow cover extent (SCE) during December was 43.48 million square km (16.79 million square miles), 500,000 square km (190,000 square miles) below the 1981-2010 average. This was the 19th smallest December SCE in the 50-year period of record for the Northern Hemisphere and smallest since 2011. The North American and Eurasian December SCE were below average.
During December, the North American SCE was slightly below average, the 22nd smallest December SCE on record. The monthly SCE was 16.83 million square km (6.50 million square miles), 200,000 square km (10,000 square miles) below average. The eastern contiguous U.S. was warmer than average, limiting snow cover there. The contiguous U.S. had its 22nd smallest December SCE. Canada had its 13th largest December SCE. Above-average SCE was observed across the Great Plains and western U.S. and the Canadian Rockies. Below-average SCE was observed across the Midwest and Northeast in the U.S. and the Great Lakes region of Canada.
The Eurasian December SCE was 26.65 million square km (10.29 million square miles), 480,000 square km (180,000 square miles) below average and the 21st smallest December SCE for Eurasia. Below-average snow cover was observed across all of Europe and parts of the Tibetan Plateau. Above-average snow cover was observed across eastern China, Mongolia, and northwestern Iran.
Sea Ice Extent
| December 2015 | Sea Ice Extent | Anomaly 1991-2020 | Trend per decade | Rank (37 years) | Record | ||||
|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | Year(s) | million km² | million mi² | |||||
| Northern Hemisphere | 12.04 | 4.65 | -2.90% | -3.55% | Largest | 32nd | 1982 | 13.64 | 5.27 |
| Smallest | 5th | 2010 | 11.83 | 4.57 | |||||
| Southern Hemisphere | 10.66 | 4.12 | +2.50% | +3.08% | Largest | 13th | 2007 | 11.98 | 4.63 |
| Smallest | 24th | 1982 | 9.22 | 3.56 | |||||
| Globe | 22.70 | 8.76 | -0.48% | -0.53% | Largest | 30th | 1988 | 24.69 | 9.53 |
| Smallest | 7th | 2006 | 21.80 | 8.42 | |||||
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2015 (37 years)
According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere (Arctic) sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for December 2015 was 12.27 million square km (4.74 million square miles), 780,000 square km (300,000 square miles), or 6.0 percent, below the 1981-2010 average. This was the fourth smallest December sea ice extent on record for the Arctic. Over the course of the month, sea ice in the Arctic expanded quickly during the beginning of the month, but slowed towards the end of the month. By the end of 2015, unusual warmth caused sea ice in the Arctic to nearly stop advancing. Sea ice coverage was below average across the Bering, Okhotsk, and Barents seas, but above average in Baffin Bay. December Arctic ice extent is decreasing at an average rate of 3.3 percent per decade.
The December Southern Hemisphere sea ice extent was 11.28 million square km (4.36 million square miles), which was less than 10,000 square km (3,900 square miles), or 0.1 percent, below the 1981-2010 average. This was the 16th smallest December Antarctic sea ice extent on record. Southern Hemisphere sea ice extent is increasing at an average rate of 2.4 percent per decade.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.