On March 4, amidst a building polar heat amplification and a strong, thousands mile long, south to north wind and storm flow across the North Atlantic and into the Arctic, sea ice extent coverage for the northern polar region plunged to new record lows.
(26 foot wave heights [left frame] and 50-60 mph sustained southerly winds [right frame] in conjunction with warm storm near the ice edge at Svalbard on March 15, 2015. Storms of this kind have been raging up through the Barents delivering powerful, warm southerly winds and immense swells to the ice edge region for at least the past half month. This strong melt pressure and warm air delivery has contributed to record low sea ice extent totals continuing for the past 13 days running. Image source: Earth Nullschool. Data source: GFS.)
Human-forced heat continued to build throughout the Arctic as warm and intensely windy storms churned northward through the Barents, bringing with them powerful swells ranging from 15 to, at times, 40 feet in height. As these great swells ground away at the ice edge, temperatures hit daily anomalies greater than 4 C above the 1979-2000 average on Sunday, March 8 for the entire Arctic region. The next day, sea ice extent, according to NSIDC, plummeted to 14,273,000 square kilometers. A value 303,000 square kilometers, or an area about the size of Arizona, smaller than the previous record low value for the date set in 2006.
Ever since March 4, the Arctic has remained in new record low territory — a period that has now lasted 13 days. Though anomalous warmth has faded somewhat — dropping today to a range of 2.65 degrees Celsius above the 1979-2000 average — sea ice has only bounced back slightly. On March 15, the NSIDC extent measure had inched up to 14,333,000 square kilometers, still about 235,000 square kilometers below the previous record low for the date.
(Arctic sea ice extent as measured by NSIDC drops below previous record low values on March 4 of 2015 [bottom dark blue line] and has remained at record low levels ever since. For reference, previous record low years for March dates include 2006 [pink line], 2007 [light blue line], and 2011 [orange line]. The top dark blue line  indicates how much sea ice extent has been lost during March over the past 36 years. Image source: NSIDC.)
Over the next week, however, these new record lows are more likely to continue to fade as warm Arctic surface temperature anomalies drop to around 1-2 C above average, the Arctic Oscillation shifts toward neutral or slightly negative, and the warm storm track through the Barents is interrupted by cold winds pushing south toward Scandinavia from the pole. Although mid-week warming forecast for Alaska and Baffin Bay may retard any potential rebound somewhat.
For the past two years, Arctic sea ice has experienced a bit of a rebound during the March through early April time-frame. This has appeared to coincide with a restrengthening of the polar Jet Stream as mid latitudes have warmed which, in turn, has weakened meridional patterns transporting heat into the Arctic during winter time. Low angle sunlight entering the Arctic at this time of year has also not yet gained enough momentum to significantly push the ice to melt. So we still have about a 2-3 week window for potential bounce-back before sunlight builds and begins to apply its steady heat forcing to the greatly diminished ice.
(Arctic Oscillation [AO] index forecast shows dip toward slightly negative or neutral AO status by end week after a rather extreme high in early March, with a return to mildly positive AO values by end month. Positive AO enhances edge melt of sea ice by encouraging storm formation at the ice edge and warm air invasions over the central ice. Image source: NOAA/CPC.)
That said, the ice is quite frail now, even with potential volume rebounds to mid 2000s levels. So even the slight addition of solar insolation may be enough to keep ice coverage values depressed in the neutral or moderately positive Arctic Oscillation regime that is predicted through the end of March. Extent measures maintaining near record lows along the 2006, 2007 and 2011 tracks, or just below, would establish a very low launching pad for a melt season that, lately, has tended to include precipitous declines in ice during the summer months.
The ongoing record low extent status, despite a return to weather patterns that are more favorable for rebound or maintenance, therefore, should be closely monitored.