NOAA's National Centers for Environmental Information
NH Snow Cover Extent
Data were provided by the Global Snow Laboratory, Rutgers University. Period of record is 1967-2009 (43-years).
As shown in the time series to the right, the average Northern Hemisphere November snow cover extent during November 2009 was above average. The Northern Hemisphere had the 13th largest snow cover extent on record. The average Northern Hemisphere November snow cover extent for the 1967-2009 period of record is 33.5 million square kilometers. Snow cover extent during autumn 2009 was the 11th largest autumn snow cover extent on record. The 43-year average Northern Hemisphere autumn snow cover extent for the period of record is 19.2 million square kilometers.
Across North America, snow cover for November 2009 was well below average, the fourth smallest extent since satellite records began in 1967. This can be attributed to anomalously warm conditions during much of the month across most of North America. According to the Environment Canada, Toronto, Ontario, Canada, set a new record for a snow-free month for the first time in recorded history. The average North American November snow cover extent is 13.3 million square kilometers for the period of record. Snow cover for autumn 2009 was the 21st lowest extent since satellite records began in 1967. The average North America autumn snow cover extent is 8.5 million square kilometers for the 43-year period of record.
Conversely, Eurasia's snow cover extent during November 2009 was above average. This was the fifth largest November snow cover extent on record. Unlike North America, most of Asia was engulfed by cooler-than-average conditions. During November 11th-12th, heavy snow fell over northern China, wreaking havoc across the region. The adverse conditions were blamed for 38 fatalities. It was reported that this was the heaviest snowfall in over five decades for the Hebei Province and the heaviest snowfall in history for the Shaanxi Province. The average Eurasian snow cover extent in November is 20.2 million square kilometers for the period of record. Eurasia's snow cover extent during autumn 2009 was the 11th largest snow cover extent on record. The 43-year average Eurasian snow cover extent in autumn is 10.7 million square kilometers for the period of record.
Sea Ice Extent
According to the National Snow and Ice Data Center (NSIDC), the November 2009 Northern Hemisphere sea ice extent—which is measured from passive microwave instruments onboard NOAA satellites—was 10.3 million square kilometers (9.3 percent or 1.1 million square kilometers below the 1979–2000 average), resulting in the third lowest November sea ice extent since satellite records began, behind 2006 and 2007. When compared to November 2007—the record low—2009 was 900,000 square kilometers above the record low. This was the 16th consecutive November with sea ice extent below average. November 1993 was the last year that had above-average sea extent. November Arctic sea ice extent has decreased at an average rate of 4.5 percent per decade since 1979. Arctic sea ice usually expands during the cold season to a March maximum, then contracts during the warm season to a September minimum.
Meanwhile, the November 2009 Southern Hemisphere sea ice extent was 0.64 percent above the 1979–2000 average. This was the 15th largest sea ice extent in November. Southern Hemisphere sea ice extent for November has increased at an average rate of 0.6 percent per decade. Antarctic sea ice usually expands during the cold season to a September maximum, then contracts during the warm season to a March minimum.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page, provided by NOAA's National Snow and Ice Data Center (NSIDC).