NOAA's National Centers for Environmental Information
NH Snow Cover Extent
| November 2018 | Snow Cover Extent | Anomaly 1991-2020 | Trend per decade | Rank (53 years) | Record | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | million km² | million mi² | million km² | million mi² | Year(s) | million km² | million mi² | |||
| Northern Hemisphere | 37.77 | 14.58 | +2.72 | +1.05 | +0.43 | +0.17 | Largest | 3rd | 1993 | 38.60 | 14.90 |
| Smallest | 51st | 1979 | 28.28 | 10.92 | |||||||
| North America | 15.72 | 6.07 | +1.85 | +0.71 | +0.18 | +0.07 | Largest | 1st | 2018 | 15.72 | 6.07 |
| Smallest | 53rd | 1979 | 11.48 | 4.43 | |||||||
| Eurasia | 22.05 | 8.51 | +0.87 | +0.34 | +0.25 | +0.10 | Largest | 13th | 1993 | 24.13 | 9.32 |
| Smallest | 41st | 1979 | 16.80 | 6.49 | |||||||
Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1966–2018 (53 years)
The Northern Hemisphere snow cover extent (SCE) for November 2018 was 37.77 million square km (14.58 million square miles), which was 3.81 million square km (1.47 million square miles) larger than the 1981–2010 average. This was the largest November SCE since 1993 and the third largest November SCE in the 53-year period of record for the Northern Hemisphere. November 2018 also marks the tenth consecutive November with above-average SCE.
The November North American SCE was 15.72 million square km (6.07 million square miles), which is 2.24 million square km (870,000 square miles) above average and the largest on record, surpassing the previous record set in 2014 (15.39 million square km or 5.94 million square miles). Snow cover was above average for much of Canada and the central and northeastern contiguous United States. Below-average SCE was observed in parts of southwestern Alaska, and the western contiguous U.S. Canada had its largest SCE in its 53-year record, the contiguous U.S. had its third largest SCE on record, while Alaska had its 21st smallest SCE on record.
The Eurasian SCE during November was 22.05 million square km (8.51 million square miles), which is 1.58 million square km (610,000 square miles) above average. This was the 13th largest November SCE on record for Eurasia. Above-average SCE was observed across parts of southern Europe, central Asia, and parts of central China. Below-average SCE was observed in ccentral Europe, western Russia, Mongolia, and southern China.
Sea Ice Extent
| November 2018 | Sea Ice Extent | Anomaly 1991-2020 | Trend per decade | Rank (40 years) | Record | ||||
|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | Year(s) | million km² | million mi² | |||||
| Northern Hemisphere | 9.82 | 3.79 | -3.16% | -5.13% | Largest | 32nd | 1982 | 11.63 | 4.49 |
| Smallest | 9th | 2016 | 8.66 | 3.34 | |||||
| Southern Hemisphere | 15.10 | 5.83 | -4.85% | +0.06% | Largest | 38th | 2013 | 16.87 | 6.51 |
| Smallest | 3rd | 2016 | 14.22 | 5.49 | |||||
| Globe | 24.92 | 9.62 | -4.19% | -1.96% | Largest | 38th | 1980 | 27.51 | 10.62 |
| Smallest | 3rd | 2016 | 22.88 | 8.83 | |||||
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2018 (40 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 November 2018 was 9.80 million square km (3.78 million square miles), which is 900,000 square km (347,000 square miles), or 8.4 percent, below the 1981–2010 average. This was the ninth smallest November Arctic sea ice extent on record and 1.14 million square kilometers (440,000 square miles) above the record low November extent set in 2016. November 2018 marks the 19th consecutive November with below-average sea ice extent.
During November 2018, sea ice extent increased faster than average for most regions. However, below-average sea ice extent was observed in the Barents Sea (sixth lowest), Bering Sea (tied with 2003 as third lowest), Chukchi (third lowest), Greenland Sea (third lowest), and Kara Sea (tied with 2017 as the ninth lowest). Above-average sea ice was observed in the Baffin Bay and the Hudson Bay. Since 1979, November Arctic sea ice extent is decreasing at an average rate of 5.0 percent per decade.
The November Southern Hemisphere (Antarctic) sea ice extent was 15.01 million square km (5.80 million square miles), which was 890,000 square km (340,000 square miles), or 5.60 percent, below the 1981–2010 average. This extent tied with 1986 as the second smallest November Southern Hemisphere sea ice extent on record, only the November sea ice extent in 2016 was smaller (10.57% below average). Antarctic sea ice declined slower than average in November.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.