NH Snow Cover Extent
|January 2017||Snow Cover Extent||1981-2010 Anomaly||Trend
(out of 51 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: 1967–2017 (51 years)
The Northern Hemisphere snow cover extent (SCE) during January was 49.18 million square km (18.99 million square miles), 2.31 million square km (890,000 square miles) above the 1981-2010 average. This was the sixth largest Northern Hemisphere SCE in the 51-year period of record and largest since 2013. The North American and Eurasian SCE were above average.
During January, the North American SCE was 500,000 square km (190,000 square miles) above the 1981-2010 average — the 13th largest on record. An active storm pattern across western North America and a winter storm in the southeastern U.S. resulted in above-average snow cover across the western and southeastern U.S. as well as the Canadian Rockies. Below-average snow cover was observed in the south-central and Mid-western United States. The contiguous U.S. SCE was the 13th largest on record, the Canadian SCE was the 10th largest on record, while the Alaska SCE was the fifth largest.
The Eurasian January SCE was 31.15 million square km (12.03 million square miles), 1.83 million square km (710,000 square miles) above average. This ranked as the seventh largest January SCE for Eurasia and the largest since 2013. Above-average snow cover was observed across central and eastern Europe, Turkey, and western China. Below-average snow cover was observed across central China and western Iran.
Sea Ice Extent
|January 2017||Sea Ice Extent||
(out of 39 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2017 (39 years)
According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere (Arctic) sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for January 2017 was 13.38 million square km (5.17 million square miles), 1.26 million square km (480,000 square miles), or 8.61 percent, below the 1981-2010 average. This was the smallest January Arctic sea ice extent on record, dipping below the previous record of 13.64 million square km (5.27 million square miles) set just last year in 2016. Sea ice extent expanded slowly in early January with ice growth nearly stopping for a week mid-month. During the third week January ice expanded rapidly, but nearly stopped once again the last week January. Below-average sea ice extent was observed in the Barents Sea, Kara Sea, and Gulf of St. Lawrence on the Atlantic side and the Bering Sea on the Pacific side. Near-average sea ice extent was observed in Baffin Bay, Labrador Sea, and Hudson Bay. January Arctic ice extent is decreasing at an average rate of 3.2 percent per decade.
The January Southern Hemisphere sea ice extent was 4.04 million square km (1.56 million square miles), which was 1.19 million square km (460,000 square miles), or 22.8 percent, below the 1981-2010 average. This was the smallest Southern Hemisphere sea ice extent on record and 280,000 square km (110,000 square miles) smaller than the previous record set in 2006. The record low January Antarctic sea ice extent comes just two years after the largest January Antarctic sea ice extent on record was observed in 2015 at 7.59 million square km (2.93 million square km). Most of the Amundsen Sea off the west coast of Antarctica was ice free by early February with near-average ice across other regions. Southern Hemisphere sea ice extent is increasing at an average rate of 3 percent per decade, with substantial inter-annual variability.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.