Sea ice shows record low growth in Chukchi, Beaufort Seas

The National Snow and Ice Data Center reports that after a quick initial freeze-up during the second half of September, ice growth slowed substantially during early October.
 “On October 20, 2016, Arctic sea ice extent began to set new daily record lows for this time of year,” the NSIDC website states. Responsible for the unprecedented low grow of sea ice were high sea surface temperatures in open water areas.
“A primary culprit behind the slow growth is that sea surface temperatures in the Beaufort and Chukchi Seas, the Barents and Kara Seas along the Eurasian coast, as well as the East Siberian Sea, were above average,” says the NSIDC.
Also, warmer than normal air temperatures inhibited the cooling of the Arctic.
According to National Weather Service Climate science and Services Manager Rick Thoman, Nome, Kotzebue and Barrow had the warmest October since record keeping began.
In Nome, weather data has been collected since 1907.
The average October temperature in Nome was 37.7°F, in Kotzebue it was 35.3°F and in Barrow it was 30.1°F.
According to the NSIDC Arctic sea ice extent averaged 2.5 million square miles in October 2016, marking the lowest sea ice growth recorded in the satellite record. This is 154,400 square miles lower than October 2007, the second lowest October extent. The average extent was 980,000 square miles below the October 1981 to 2010 long-term average.
However, Thoman also observed that multiyear sea ice that floated about 30 miles offshore from northern Alaska survived the summer, but melted during the course of September and was completely gone in October. By October 31, the Arctic sea ice extent stood at 2.73 million square miles, the lowest extent in the satellite record for that date. Thoman notes that the slowest growth occurred in the Chukchi and Beaufort seas. “As of Halloween, the combined ice growth was the lowest for the Chukchi and Beaufort, where the combined ice extent was the lower than any other low growth year,” he said.
Since the fall sea surface temperatures were significantly warmer than normal, it took longer for the sea to cool off and freeze up. Thoman said September water temperatures were 2° to 4°F warmer than normal. Another factor of inhibiting sea ice growth was the steady flow of warm air from a sustained high pressure system located over eastern Alaska and the Yukon.
Thoman noted that cold weather in November — Nome’s temperatures were on track with what is normal, namely an average temperatures of 17.3°F — is conducive to sea ice growth. Satellite images show that the Beaufort Sea is iced up, that ice grows in the Chukchi Sea and that the ice edge is still well north of the Bering Strait. Nearshore ice growth is shown at eastern Norton Sound and along the northern shores of the Seward Peninsula. Since sea ice growth began a month later than usual, the late formation of ice has consequences in terms of thickness and stability, which in turn causes unpredictability for subsistence hunters. “We lost a month of the season that we don’t get back and that impacts sea ice thickness and ridging,” Thoman said.
As for the near future, Thoman expects weather patterns that are consistent with La Nina winters. Coming out of the El Nino cycle, La Nina winters are more typical for normal, meaning colder, winter temperatures and weather. But Thoman also said that it is common for La Nina winters to have big swings in temperatures. “Extended periods of either warmer or colder weather are common during La Nina winters,” he said.