Global Snow and Ice - February 2013
NH Snow Cover Extent
Beginning with the February 2013 report, the base period for hemispheric and continental snow cover extents and hemispheric sea ice extents in this report will change to the 1981-2010 30-year period. All anomalies and departures from average will be with respect to the 1981-2010 period.
|February 2013||Snow Cover Extent||1981-2010 Anomaly||Trend
(out of 47 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: 1967–2013 (47 years)
The Northern Hemisphere snow cover extent (SCE) during February 2013 was above average and ranked as the 16th largest February SCE in the 47-year period of record. The monthly SCE was 1.3 million square km (510,000 square miles) above the 1981-2010 average of 45.2 million square km (17.5 million square miles). Both the Eurasian and North American land areas experienced above-average SCE during February. For the winter period (December 2012—February 2013), the Northern Hemisphere had an above-average SCE — the fourth largest on record at 2.1 million square km (0.8 million square miles) above the 1981-2010 average of 45.1 million square km (17.4 million square miles). The winter seasons of 1977/78, 2009/10, and 2010/11 had larger Northern Hemisphere snow cover extents.
During February 2013, the North American SCE was 543,000 square km (210,000 square miles) above the 1981-2010 average of 17.0 million square km (6.6 million square miles) and was the 14th largest monthly SCE on record. Canada experienced its largest February SCE on record, while the contiguous U.S. had its 17th largest February SCE. According to analysis by the Rutgers Global Snow Lab, above-average snow cover was observed in the central and northeastern United States, as well as western Canada and the Great Lakes region of both countries. For the winter season, the North American SCE was 17.5 million square km (6.8 million square miles), 433,000 square km (167,000 square miles) above the 1981-2010 average.
The Eurasian SCE during February 2013 was 776,000 square km (300,000 square miles) above the 1981-2010 average of 29.0 million square km (11.2 million square miles), and the 18th largest monthly SCE on record. Much of western and central Europe, the Himalayas, and northeastern China experienced above-average snow cover during February. Below-average snow cover was present for eastern Europe and western Asia, including the Balkans, Turkey, Iran, and Kazakhstan. Below-average snow cover was also present for central Asia. For the winter, the snow cover extent was 29.6 million square km (11.4 million square miles), which was 1.6 million square km (620,000 square miles) above the 1981-2010 average and the fourth largest winter SCE for Eurasia. The winter seasons of 1977/78, 2002/03, and 1971/72 had larger snow cover extents.
Sea Ice Extent
|February 2013||Sea Ice Extent||
(out of 35 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
|Southern Hemisphere||3.87||1.49||+27.30%||+3.62%||Largest||1ˢᵗ||2003, 2008, 2013||3.87||1.49|
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 February 2013 was 14.66 million square km (5.66 million square miles), 4.47 percent below the 1981-2010 average, and the seventh smallest February extent on record. This was the largest February Arctic sea ice extent since 2009. Despite the large sea ice extent, compared to recent years, the ten smallest February Arctic sea ice extents have occurred in the past ten years. Monthly-averaged Arctic sea ice extent during the month of February has failed to reach 15.0 million square km (5.79 million square miles) since 2008. Prior to 2004, the February average sea ice extent had not been less than 15.0 million square km (5.79 million square miles). February Arctic ice extent is decreasing at an average rate of 3.0 percent per decade.
During February, the Arctic sea ice continued to expand, with the end of the growth season typically occurring during March. The Arctic gained 766,000 square km (296,000 square miles) of ice during the month, which was above average. Despite the faster-than-average ice expansion, sea ice remained below average in most areas of the Arctic, with the exception of the Bering Sea, where above-average ice was observed.
The February 2013 Southern Hemisphere sea ice extent was 3.8 million square km (1.5 million square miles), 25.86 percent above the 1981-2010 average, and the third largest monthly Antarctic sea ice extent on record. February of 2003 and 2008 had larger monthly sea ice extents. The Weddell Sea continued to experience much-above-average sea ice extent during the month, contributing to the large monthly average. February Southern Hemisphere sea ice extent is increasing at an average rate of 3.6 percent per decade, with substantial interannual variability.
February marked the end of the Antarctic sea ice melt season. The annual minimum extent of sea ice occurred on February 20th at 3.68 million square km (1.42 million square miles) and began its annual expansion. This marked the second largest annual minimum sea ice extent for the Antarctic. The largest annual sea ice minimum extent occurred in February 2008 at 3.69 million square km (1.43 million square miles).
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.