Global Snow and Ice - March 2021
NH Snow Cover Extent
|March 2021||Snow Cover Extent||1981-2010 Anomaly||Trend
(out of 55 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: 1967–2021 (55 years)
The Northern Hemisphere snow cover extent during March 2021 was 38.61 million square km (14.91 million square miles). This was 1.52 million square km (590,000 square miles)—equivalent to the size of the country of Mongolia—below the 1981–2010 average. The March 2021 Northern Hemisphere snow cover extent was the 12th smallest March extent in the 55-year satellite record and marked the third consecutive March with below-average snow cover extent.
The North America snow cover extent was the ninth smallest March snow cover extent on record at 14.92 million square km (5.76 million square miles), which was 720,000 square km (280,000 square miles)—or about the size of Zambia—below average. This was the smallest March snow cover extent since 2016. Across North America, parts of southern Canada and much of northern and western parts of the contiguous U.S. had below-average snow cover extent. Meanwhile, above-average snow cover extent was limited to parts of the Pacific Northwest and central Rocky Mountains. Alaska's March snow cover extent tied with three other years as the largest March snow cover extent on record. Meanwhile, Canada and the United States had a below-average March snow cover extent, ranking as the tenth and seventh smallest March snow cover extent in the 55-year record, respectively.
Eurasia's snow cover extent during March 2021 was 23.69 million square km (9.15 million square miles) or 800,000 square km (310,000 square miles) below average. This was the third consecutive March that Eurasia had below-average snow cover extent and was the 14th smallest for March on record. Below-average snow cover extent was observed across much of eastern Europe and parts of southwestern and southern Asia, and across Mongolia and northeastern and southern China. Above-average March snow cover extent was present across parts of western Russia, northern Kazakhstan, and scattered across parts of eastern Asia.
Sea Ice Extent
The sea ice extent data for the Arctic and Antarctic are provided by the National Snow and Ice Data Center (NSIDC) and are measured from passive microwave instruments onboard NOAA Satellites. The sea ice extent period of record is from 1979–2021 for a total of 43 years.
|March 2021||Sea Ice Extent||
(out of 43 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2021 (43 years)
The Arctic sea ice extent for March 2021 was 5.1% below average or 790,000 square km (305,000 square miles)—equivalent to the size of Mozambique— below the 1981–2010 average. This was the ninth smallest March sea ice extent since satellite records began in 1979. The NSIDC stated that below-average March sea ice extent was observed on the Pacific side of the Bering Sea and the Atlantic side of the northern Barents Sea as well across parts of the Arctic in the Gulf of St. Lawrence. Baffin Bay's and the Gulf of St. Lawrence regional sea ice extents were the fourth (tied with 2010) and third smallest (tied with 2011) March extent on record, respectively. Elsewhere had close to average sea ice extent. It was also reported by the NSIDC that the low sea ice extent in the Gulf of St. Lawrence was leading to the death of many harp seal pups since the pups were forced to cluster on shore and thus were vulnerable to predators.
According to the preliminary data from the NSIDC, the Arctic sea ice extent reached its annual maximum extent of 14.77 million square km (5.70 million square miles) on March 21, 2021. This value was 870,000 square km (336,000 square miles)—equivalent to the size of the country of Pakistan—below the 1981–2010 average. This year's maximum annual extent took place nine days later than the median of March 12 and tied with 2007 as the seventh smallest annual maximum extent in the 43-year satellite record. The smallest annual maximum extent was set on March 7, 2017 at 14.41 million square km (5.56 million square miles).
The Antarctic sea ice extent during March 2021 was 4.45 million square km (1.72 million square miles), which is 10.4%, or 420,000 square km (160,000 square miles), above average. This was the largest March Antarctic sea ice extent since 2015 and the tenth largest since records began in 1979. According to NSIDC, the sea ice extent grew rapidly after reaching its annual minimum extent on February 21. During February 25–March 8, the Antarctic sea ice extent grew by over 1 million square km (386,000 square miles)—the fastest growth for this time of year on record.