Global Snow & Ice - April 2014
NH Snow Cover Extent
|April 2014||Snow Cover Extent||1981-2010 Anomaly||Trend
(out of 48 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: 1967–2014 (48 years)
The Northern Hemisphere snow cover extent (SCE) during April 2014 was 28.55 million square km (11.03 million square miles), which was 1.67 million square km (640,000 square miles) below the 1981-2010 average. This was the sixth smallest April SCE for the Northern Hemisphere in the 48-year period of record. The Eurasian SCE was record small, while the North American SCE was above average. The Northern Hemisphere SCE during April is decreasing at an average rate of 490,000 square km (190,000 square miles), or 1.6 percent, per decade.
The April North American SCE was 13.79 million square km (5.32 million square miles), which was 750,000 square km (290,000 square miles) above the 1981-2010 average. This was the 14th largest April SCE on record for North America. In Canada, above-average snow cover was observed across most of the country, with the highest departures from average across the Canadian Rockies and the Southern Prairies. Canada had its tenth largest April SCE on record. In the U.S., above-average snow cover was observed across the central Rockies and Plains and the western Great Lakes region. Below-average snow cover was observed across parts of the Northeast, Northern Plains, and much of the West. Below-average snow cover was also observed across much of Alaska. The contiguous U.S. had a slightly below-average SCE during April, while the Alaskan SCE was the sixth smallest on record. Although April SCE was above average this year for North America, the continental SCE during April is decreasing at an average rate of 110,000 square km (42,000 square miles), or 0.8 percent per decade.
The Eurasian SCE during April was 14.77 million square km (5.70 million square miles), 2.40 million square km (930,000 square miles) below the 1981-2010 average, and the smallest April SCE on record. The 2014 April SCE for Eurasia was 260,000 square km (100,000 square miles) smaller than the previous record small April SCE that occurred in 2008, this difference is approximately the size of New Zealand. A large portion of Asia and Europe, particularly Siberia, experienced very warm April temperatures, which coincided with below-average snow cover observed across much of northern Europe, central and eastern Russia, Turkey, Kazakhstan, and Mongolia. Above-average snow cover was observed in the Ural region of Russia and parts of the Tibetan Plateau. April SCE across Eurasia is decreasing at an average rate of 380,000 square km (145,000 square miles), or 2.2 percent per decade.
Sea Ice Extent
|April 2014||Sea Ice Extent||
(out of 36 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2014 (36 years)
According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for April 2014 was 14.14 million square km (5.46 million square miles), which was 610,000 square km (240,000 square miles), or 4.1 percent, below the 1981-2010 average. The April 2014 Arctic sea ice extent was 270,000 square kilometers (104,000 square miles) larger than the record smallest April sea ice extent that occurred in 2007, and ranked as the fifth smallest April Arctic sea ice extent on record. Sea ice in the Arctic declined rapidly during the first half of the month, but the seasonal melt slowed during the second half of the month with a total monthly ice loss rate below average. Below-average sea ice was observed in the Barents Sea, Sea of Okhotsk, and the Bering Sea, with above-average sea ice in the Baffin Bay. The rest of the Arctic had near-average sea ice cover. April Arctic sea ice extent is decreasing at an average rate of 2.3 percent per decade.
The April 2014 Southern Hemisphere sea ice extent was 9.00 million square km (3.47 million square miles), 1.60 million square km (610,000 square miles), or 21.6 percent, above the 1981-2010 average. The was the largest April sea ice extent on record for the Southern Hemisphere, surpassing the previous record set in 2008 by 320,000 square km (120,000 square miles), this difference is approximately the size of Norway. This marks the 16th consecutive month with much-above average sea ice extent in the Southern Hemisphere. Much above-average sea ice was observed in the eastern Waddell Sea, with above-average sea ice along the South Indian Ocean coast of Antarctica. Despite the record setting sea ice, many locations in Antarctica had monthly temperatures that were much above average, with temperatures up to 7°F above average near the South Pole, according to the NSIDC. Southern Hemisphere sea ice extent during April is increasing at an average rate of 3.4 percent per decade, with substantial interannual variability.
When combining the Northern and Southern Hemisphere sea ice extents, the globally-averaged sea ice extent during April was 23.14 million square km (8.93 million square miles), 4.5 percent above the 1981-2010 average and the third largest April global sea ice extent on record, behind 1979 and 1982. Global sea ice extent during April is decreasing at an average rate of 0.5 percent per decade.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.