Global Snow and Ice - January 2018
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
|January 2018||Snow Cover Extent||1981-2010 Anomaly||Trend
(out of 52 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: 1967–2018 (52 years)
The Northern Hemisphere snow cover extent (SCE) for January 2018 was 46.93 million square km (18.12 million square miles), which is 60,000 square km (200,000 square miles), or 0.1 percent, smaller than the 1981-2010 average. This ranked near the median value in the 52-year period of record for the Northern Hemisphere. The North American and Eurasian SCE were both near average during January.
During January, the North American SCE was slightly larger than average and ranked near the median value in the 52-year period of record. The monthly SCE was 17.59 million square km (6.79 million square miles), 50,000 square km (20,000 square miles) above average. In the U.S., above-average snow cover was observed in the Northern Rockies, Central Plains and Northeast. Below-average snow cover was observed across much of the West, Southeast and Southern Plains. In Canada, above-average snow cover was observed in the Rockies and Maritime Provinces with below-average in parts of the southern prairies. The contiguous U.S. SCE was slightly below average, while the Canadian SCE ranked as the seventh highest for the month. The Alaska SCE was above average.
The Eurasian January SCE was 29.34 million square km (11.32 million square miles), 20,000 square km (10,000 square miles) above average and ranked near the median value. Above-average snow cover was observed in Japan, the Korean peninsula, eastern and central China, southern Mongolia, southern Kazakhstan and part of Northern Africa where snow fell in the Western Sahara. Below-average snow cover was observed across most of Europe, Turkey, western Iran and central Asia.
Sea Ice Extent
|January 2018||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: 1979–2018 (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 2018 was 13.06 million square km (5.04 million square miles), 1.36 million square km (525,000 square miles), or 9.4 percent, below the 1981-2010 average. This was the smallest January sea ice extent on record for the Arctic, dipping below the previous record set just last year at 13.17 million square km (5.08 million square miles). Sea ice coverage was below average in the Barents, Kara and Bering Seas with near-average ice coverage in Greenland Sea and the Sea of Okhotsk. The sea ice coverage in the Barents Sea was the second smallest on record during January. The Arctic sea ice extent expanded at a slightly slower than average rate during the month. Since 1979, January Arctic ice extent is decreasing at an average rate of 3.3 percent per decade.
The January Southern Hemisphere sea ice extent was 4.13 million square km (1.59 million square miles), which was 870,000 million square km (340,000 square miles), or 17.4 percent, below the 1981-2010 average. Much-below-average sea ice was observed in the Ross and West Amundsen Seas. This was the second smallest January Antarctic sea ice extent record. Only the January Antarctic sea ice extent in 2017 was smaller at 3.74 million square km (1.44 million square miles). Southern Hemisphere sea ice extent is increasing at an average rate of 1.8 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.