NOAA's National Centers for Environmental Information
NH Snow Cover Extent
| March 2019 | 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 | 39.48 | 15.24 | -0.31 | -0.12 | -0.41 | -0.16 | Largest | 37th | 1985 | 44.28 | 17.10 |
| Smallest | 17th | 1990 | 37.12 | 14.33 | |||||||
| North America | 16.58 | 6.40 | +0.88 | +0.34 | -0.03 | -0.01 | Largest | 9th | 1969 | 17.29 | 6.68 |
| Smallest | 45th | 1968 | 14.04 | 5.42 | |||||||
| Eurasia | 22.90 | 8.84 | -1.19 | -0.46 | -0.38 | -0.15 | Largest | 47th | 1981 | 27.95 | 10.79 |
| Smallest | 7th | 2002 | 21.18 | 8.18 | |||||||
Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1967–2019 (53 years)
The Northern Hemisphere snow cover extent (SCE) for March 2019 was below average at 39.48 million square km (15.24 million square miles). This was 1.6% or 650,000 square km (250,000 square miles) smaller than the 1981–2010 average and the 17th smallest March SCE in the 53-year period of record for the Northern Hemisphere. This was also the smallest March SCE since 2016. The below-average SCE across the Northern Hemisphere could be attributed to the exceptionally warm temperatures across much of the land surface across the Northern Hemisphere northern latitudes, particularly across Alaska, northwestern Canada, Europe, and much of northern Asia, where in some locations temperatures were as high as 5.0°C (9.0°F) above the 1981–2010 average. Cooler-than-average conditions across the Northern Hemisphere land were limited to southern and eastern Canada, parts of southern and northeastern Asia, and across much of the contiguous U.S.
The March North American SCE was 16.58 million square km (6.40 million square miles), which is 6.0% or 940,000 square km (360,000 square miles) above average. This was the second consecutive year with March SCE above average and the ninth largest North American SCE in the 53-year record. Above-average snow cover was observed across much of the northern half of the contiguous U.S. Below-average SCE was limited to parts of western Canada and the U.S. Rocky Mountains. Canada's March 2019 SCE was near average, ranking as the 24th smallest (or 30th largest) in its 53-year record, while the contiguous U.S. had its sixth largest SCE on record. Alaska had its third largest March SCE on record.
The Eurasian SCE during March was 22.90 million square km (8.84 million square miles), which is 6.5% or 1.59 million square km (610,000 square miles) below average. This was the seventh smallest March SCE on record for Eurasia. Below-average SCE was observed across much of central and eastern Europe, and across parts of Khazakstan, eastern Mongolia, and northeastern China. Meanwhile, above-average SCE was limited to parts of western China, Afgahnistan, and parts of western Russia.
Sea Ice Extent
| March 2019 | Sea Ice Extent | Anomaly 1991-2020 | Trend per decade | Rank (41 years) | Record | ||||
|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | Year(s) | million km² | million mi² | |||||
| Northern Hemisphere | 14.57 | 5.63 | -3.06% | -2.73% | Largest | 34th | 1979 | 16.34 | 6.31 |
| Smallest | 8th | 2017 | 14.29 | 5.52 | |||||
| Southern Hemisphere | 3.17 | 1.22 | -22.30% | +1.72% | Largest | 40th | 2008 | 5.28 | 2.04 |
| Smallest | 2nd | 2017 | 2.70 | 1.04 | |||||
| Globe | 17.74 | 6.85 | -7.17% | -1.73% | Largest | 39th | 2008 | 20.46 | 7.90 |
| Smallest | 3rd | 2017 | 16.99 | 6.56 | |||||
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2019 (41 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 March 2019 was 14.55 million square km (5.62 million square miles), which is 880,000 square km (340,000 square miles) or 5.7% below the 1981–2010 average. This value tied with 2011 as the seventh smallest March Arctic sea ice extent on record. The record low March sea ice extent occurred in 2017 at 14.29 million square km (5.52 million square miles). March 2019 marks the 16th consecutive March with below-average sea ice extent. March 2003 was the last time the March sea ice extent was above average. Since 1979, March Arctic sea ice extent is decreasing at an average rate of 2.7 percent per decade.
The Bering Sea had near-record low sea ice extent during March 2019, with a sea ice extent that was 53% or 450,000 square km (170,000 square mi) below the 1981–2010 average. Only March 2018 was smaller at 460,000 square km (180,000 square mi) below average or 55% below average March sea ice extent. The Baffin Bay and Barents and Greenland seas were below average for March. Although the Barents sea ice extent was below average, it was the highest sea ice extent since 2013. Greenland Sea had its third smallest sea ice extent at 25% below average, behind 2018 (35% below average) and 2016 (29% below average).
The Arctic sea ice expands during the Northern Hemisphere cold season, typically reaching a maximum extent in March. Once the maximum extent is reached, it marks the beginning of the Arctic melt season. On March 13 the Arctic reached its annual maximum sea ice extent at 14.78 million square km (5.71 million square miles), tying with 2007 as the seventh smallest maximum extent on record. March 13 is only one day later than the 1981–2010 median date of March 12 for the maximum sea ice extent to be reached. According to NSIDC, the ten smallest maximum Arctic sea ice extents in the 41-year satellite record have occured since 2005, with the three smallest extents occurring since 2015.
The March Southern Hemisphere (Antarctic) sea ice extent was 3.16 million square km (1.22 million square miles), which was 870,000 square km (340,000 square miles), or 21.59 percent, below the 1981–2010 average. This extent was the third consecutive year with below-average March sea ice extent and the second smallest March Southern Hemisphere sea ice extent on record. Only March 2017 was smaller at 33.0% below average.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.