Global Snow and Ice - November 2012
Beginning in November 2017, NCEI will use version 3 of the National Snow and Ice Data Center's (NSIDC) monthly sea ice extent index. All historical monthly sea ice extent values will be updated to version 3, but historical reports will not be updated. For additional information on the methodology changes and comparisons to version 2, please visit the National Snow and Ice Data Center.
NH Snow Cover Extent
Data were provided by the Global Snow Laboratory, Rutgers University. Period of record is 1967-2012 (47 years).
The Northern Hemisphere snow cover extent during November 2012 was above-average, ranking as the fifth largest on record for the month, and marked the fourth consecutive November with above-average snow cover for the hemisphere. The Northern Hemisphere snow cover extent was 36.0 million square km (13.9 million square miles), 2.3 million square km (889,000 square miles) above average. The autumn season (September-November) snow cover extent was above average, and ranked as the 10th largest (37th smallest) in the 47-year period of record.
During November, the North American snow cover extent was above average and ranked as the 12th largest on record. The monthly snow cover extent was 13.9 million square km (5.4 million square km), 590,000 square km (227,800 square miles) above average. This was the third consecutive November with above-average snow cover extent for the continent and the largest since November 2003. Several large storms hit the west coast of North America during the month, with above-average snow cover occurring across the Canadian Rockies and Prairies and extending into the north-central United States. Below-average snow cover was observed across the U.S. Rockies, Central Plains, Midwest, and Northeast and eastern Canada. For the autumn season, North American snow cover was above average and ranked as the 15th largest (32nd largest) seasonal snow cover extent for the continent. For more information on the U.S. November 2012 snow events, please visit the U.S. November Snow/Ice Summary page.
Eurasian snow cover was above average in November and ranked as the eighth largest on record at 22.0 million square km (8.5 million square miles), 1.7 million square km (656,000 square miles) above average. Much of Russia, Mongolia, and eastern China experienced above-average snow cover during November, while southeastern Russia, Turkey, and the Tibetan Plateau had below-average snow cover. The autumn snow cover extent was also above average and ranked as the 12th largest (35th smallest) on record for the continent.
Sea Ice Extent
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 November 2012 was 9.93 million square km (3.83 million square miles). The monthly sea ice extent was 12.19 percent below average and the third smallest November Arctic sea ice extent in the satellite record. Only the November sea ice extents in 2006 and 2010 were smaller. This was the 19th consecutive November and 138th consecutive month with below-average Arctic sea ice extent. November Arctic sea ice extent has decreased at an average rate of 4.8 percent per decade.
Arctic sea ice expanded rapidly during November, at a rate of 98,600 square km (38,100 square miles) per day which is faster than average for the month. By the end of the month, the central Arctic Ocean had completely refrozen and the Bering Sea had above-average sea ice coverage. The Barents and Kara seas were much slower to freeze, both of which continued to be mostly ice free by the end of November. Below-average ice cover was observed for Baffin and Hudson Bays.
The November 2012 Southern Hemisphere sea ice extent was 16.62 million square km (6.42 million square miles), 2.36 percent above average and the sixth largest November sea ice extent in the 1979-2012 period of record. Antarctic sea ice extent during November has increased at an average rate of 0.7 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.