Global Snow & Ice - December 2013
NH Snow Cover Extent
|December 2013||Snow Cover Extent||1981-2010 Anomaly||Trend
(out of 48 years)
|million km2||million mi2||million km2||million mi2||million km2||million mi2||Year(s)||million km2||million mi2|
Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1966–2013 (48 years)
The Northern Hemisphere snow cover extent (SCE) during December was 45.3 million square km (17.5 million square miles), 1.3 million square km (500,000 square miles) above the 1981-2010 average. This was the eighth largest December SCE on record for the Northern Hemisphere. The largest December SCE on record for the Northern Hemisphere occurred one year prior, in 2012. Above-average SCE was observed in both North America and Eurasia.
During December, the North American SCE was above average, ranking as the seventh largest December SCE on record. The monthly SCE was 17.9 million square km (6.9 million square miles), 1.1 million square km (410,000 square miles) above average. This was the largest December SCE for North America since 2009. Numerous winter storms impacted the contiguous U.S. during December, causing the above-average SCE. The contiguous U.S. had its eighth largest December SCE, while Canada had its fourth largest. Above-average SCE was observed across the Rockies Mountains, the Northern Plains and Midwest regions of the U.S., and across the Great Lakes region. Below-average SCE was observed across the western United States.
The Eurasian December SCE was 27.4 million square km (10.6 million square miles), 229,000 square km (100,000 square miles) above average and the 20th largest December SCE for Eurasia. Below-average snow cover was observed across much of Western Europe, northern China, and the Tibetan Plateau. Above-average snow cover was observed across Eastern Europe, Turkey, Kazakhstan, and central China.
Sea Ice Extent
|December 2013||Sea Ice Extent||
(out of 34 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2013 (34 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 December 2013 was 12.38 million square km (4.78 million square miles), 700,000 square km (270,000 square miles), or 5.2 percent, below the 1981-2010 average. This was the fourth lowest December sea ice extent on record for the Arctic. The Arctic gained about 1.85 million square km (714,000 square miles) of ice during December, slightly less than average. The smallest December Arctic sea ice extent occurred in 2010 at 12.02 million square km (4.64 million square miles). Sea ice coverage was below average in the Barents Sea, the Bering Sea, and the Sea of Okhotsk. Near-average sea ice was observed in both the Greenland Sea and Baffin Bay. December Arctic ice extent is decreasing at an average rate of 3.5 percent per decade.
The December Southern Hemisphere sea ice extent was 12.63 million square km (4.88 million square miles), which was 1.36 million square km (530,000 square miles), or 12.1 percent, above the 1981-2010 average. This ranked as the second largest December Antarctic sea ice extent on record, ending a four month streak (August–November) of record large sea ice in the Southern Hemisphere. The largest December Antarctic sea ice occurred in 2007, and was about 40,000 square km (10,000 square miles) larger than the December 2013 sea ice extent. Southern Hemisphere sea ice extent is increasing at an average rate of 2.3 percent per decade, with substantial interannual variability.
When combining the Northern Hemisphere and Southern Hemisphere sea ice extents, the globally-averaged sea ice extent during December was 25.01 million square km (9.66 million square miles), 2.8 percent above the 1981-2010 average, and the fifth largest December global sea ice extent on record. This was the largest December global sea ice extent since 2007. December global sea ice extent is declining at an average rate of 0.8 percent per decade.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.