Sea Ice Today

Arctic sea ice extent declined slowly through the first three weeks of April, compared to recent years. The slow decline through March and the first few weeks of April meant that by mid-April, ice extent was at near-average levels.

Update, April 19, 2012: The nine-day trailing average climatology on the daily data graph has been changed to a five-day trailing average, to be consistent with the five-day trailing average for the daily data.

Arctic sea ice reached its annual maximum extent on March 18, after reaching an initial peak early in the month and declining briefly. Ice extent for the month as a whole was higher than in recent years, but still below average.

On March 18, 2012, Arctic sea ice extent reached its annual maximum extent, marking the beginning of the melt season for Northern Hemisphere sea ice. This year’s maximum extent was the ninth lowest in the satellite record.

As in January, sea ice extent in February was low on the Atlantic side of the Arctic, but unusually high on the Pacific side of the Arctic, remaining lower than average overall.

Overall, Arctic sea ice extent remained lower than average in January. However, in the Bering Sea, ice extent was much greater than normal.

Arctic sea ice extent remained unusually low through December, especially in the Barents and Kara seas.  In sharp contrast to the past two winters, the winter of 2011 has so far seen a generally positive phase of the Arctic Oscillation, a wea

Arctic sea ice continued its winter expansion, although ice growth slowed briefly in early November. The slowdown may have been related to a strong Arctic storm that tracked from the Bering Sea into the Beaufort and Chukchi seas.

Arctic sea ice extent increased rapidly through October, as is typical this time of year. Large areas of open water were still present in the Beaufort and Chukchi seas at the end of the month.

The summer sea ice melt season has ended in the Arctic. Arctic sea ice extent reached its low for the year, the second lowest in the satellite record, on September 9.

In the last few days, the decline in Arctic sea ice extent has slowed. NSIDC data show Arctic sea ice extent currently at the second-lowest levels in the satellite record.

Arctic sea ice extent averaged for August 2011 reached the second lowest level for the month in the 1979 to 2011 satellite record. Both the Northwest Passage and the Northern Sea route appear to be open.

After a period of slow melt from late July through early August, Arctic ice extent is again declining at a brisk pace, but remains higher than for 2007, the record low year. Data also indicate continued thinning of the ice.

Arctic sea ice extent averaged for July 2011 reached the lowest level for the month in the 1979 to 2011 satellite record, even though the pace of ice loss slowed substantially during the last two weeks of July.

Arctic sea ice extent declined at a rapid pace through the first half of July, and is now tracking below the year 2007, which saw the record minimum September extent.

Arctic sea ice extent for June 2011 was the second lowest in the satellite data record since 1979, continuing the trend of declining summer ice cover.

Arctic sea ice extent for May 2011 was the third lowest in the satellite data record since 1979, continuing the long-term decline.

Arctic sea ice declined slowly through most of April. Because of the slow decline in April, ice extent for the month as a whole did not approach record lows, as it did in March.

Arctic sea ice extent for the month of March 2011 was the second lowest in the satellite record. Sea ice reached its maximum extent on March 7; extent on this date tied for the lowest winter maximum extent in the satellite record.