Global Snow and Ice - Annual 2015
Issued: 20 January 2016
NH Snow Cover Extent
The Northern Hemisphere snow cover extent (SCE) during winter (December 2014-February 2015) was 60,000 square km (23,000 square miles) below the 1981-2010 average — the 20th smallest winter SCE for the Northern Hemisphere since records began in 1967 and smallest since 2006-07. This was the first winter since 2009-10 that the Northern Hemisphere SCE was below average. The North American winter SCE was slightly below average while the Eurasian winter SCE was slightly above average. Northern Hemisphere winter SCE has changed only slightly in the 49-year record, with a seasonal increase of about 0.4 percent per decade. For the spring season (March-May), the three-month average SCE for the Northern Hemisphere was 1.27 million square km (490,000 square miles) below average and the eighth smallest spring SCE for the Northern Hemisphere. The North American spring SCE was the fourth smallest on record while the Eurasian spring SCE was the 14th smallest. The Northern Hemisphere spring SCE has decreased at an average rate of 2.4 percent per decade.
Across North America during the 2014-15 winter, the SCE was 70,000 square km (27,000 square miles) below the 1981-2010 average, the 22nd largest on record. This was the smallest winter SCE for North America since 2011-12. For December and January, the North American SCE was slightly below average with below-average snow cover across western parts of the continent. The February SCE was slightly above average, with above-average snow cover across the eastern half of the continent and below-average snow cover across the western half. The North American SCE for winter is increasing at an average rate of 0.3 percent per decade. For the spring season, the North American SCE was 740,000 square km (286,000 square miles) below average and the fourth smallest on record and smallest since 2012. Three of the four smallest spring snow cover extents for North America have occurred since 2010. The March SCE was the tenth smallest, the April SCE was the 15th smallest, and the May SCE was the third smallest. The spring SCE for North America is decreasing at an average rate of 1.3 percent per decade. For more information on the snow season across the U.S., please read the U.S. annual snow report.
In Eurasia, the winter SCE for 2014-15 was 10,000 square km (3,900 square miles) above average but the 22nd smallest winter SCE for the continent. It was also the smallest winter SCE for the continent since 2008-09. The Eurasian SCE was slightly above average for December and January and much below-average for February ranking as the ninth smallest on record. For the entire season, SCE for Eurasia is increasing at an average rate of 0.4 percent per decade. For the spring season, the Eurasian SCE was 530,000 square km (205,000 square miles) below average and the 14th smallest on record. The March SCE was the ninth smallest on record, the April SCE was the 21st largest, and the May SCE was the 12th smallest. The spring SCE for Eurasia is decreasing at an average rate of 3.4 percent per decade.
Sea Ice Extent
Arctic sea ice, which is measured from passive microwave instruments onboard NOAA satellites, usually expands during the cold season to a March maximum, and then contracts during the warm season to a September minimum. According to the National Snow and Ice Data Center (NSIDC), during each month of 2015, the Arctic sea ice extent was below average. When averaged for the entire year, the Arctic sea ice extent was 10.76 million square km (4.25 million square miles), the fifth smallest on record.
Daily Arctic Sea ice extent through 2015
The annual maximum sea ice extent for the Arctic occurred on February 25th at 14.54 million square km (5.61 million square miles). This was the lowest maximum Arctic sea ice extent in the satellite record. Below-average ice was experienced in most regions with the exception of the Labrador Sea and the Davis Strait. The maximum extent is 1.10 million square km (425,000 square miles) below the 1981-2010 average and 130,000 square km (50,200 square miles) below the previous record smallest annual maximum that occurred in 2011. The February 25th date of the maximum was 15 days earlier than the 1981-2010 average of March 12. The earliest date of the annual maximum was February 24th in 1996.
Arctic sea ice minimum 2015
On September 11th, the Artic sea ice extent reached its annual minimum, four days earlier than average. The 2015 minimum was 4.41 million square km (1.70 million square miles), 1.81 million square km (699,000 square miles) below the 1981-2010 average, but 1.02 million square km (394,000 square miles) larger than the smallest annual minimum extent that occurred in 2012. The 2015 minimum extent was the fourth smallest in the satellite record behind 2012, 2007, and 2011. The nine lowest minimum extents in the satellite era have all occurred in the last nine years. From the annual maximum extent that occurred on February 25th to the minimum extent, the Arctic lost a total of 10.13 million square km (3.91 million square miles) of ice, which was 1.68 million square km (651,000 square miles) less than the record ice loss that occurred in 2012.
Antarctic sea ice typically contracts during the Southern Hemisphere warm season to a minimum extent in late summer (February or March) and expands during the cold season to a September maximum extent. Antarctic sea ice was much above-average during the first half of 2015, with record and near-record large ice extents from January-July. The Antarctic sea ice extent in January, April, and May was record large. When averaged for the entire year, the Antarctic sea ice extent was 12.74 million square km (4.92 square miles), the third largest on record.
Daily Antarctic Sea ice extent through 2015
The Antarctic sea ice reached its annual minimum extent on February 20th at 3.58 million square kilometers (1.38 million square miles). This was the fourth highest minimum ice extent on record for the Southern Hemisphere, trailing behind the annual minimum extents in 2008, 2013, and 2004. The annual minimum extent has varied greatly over the past few years, approaching record low levels in 2011 and record high levels in 2013.
The Antarctic sea ice extent continued reached its annual maximum extent on October 6th at 18.83 million square km (7.24 million square miles), 120,000 square km (46,000 square miles) above the average. This was the 16th largest maximum extent on record, in contrast to the past three years when record large maximum sea ice extents were observed.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.