Images (click to enlarge): Arctic sea ice extent, November 5, 2011, from National Snow and Ice Data Center; GFS model forecast weather map for northern Pacific and Alaska, November 9, 2011, from NCEP/National Weather Service.
See update for later information.
Original post:
Although it didn't quite break the record low of 2007, this year's minimum Arctic ice extent was the second lowest since satellite observations began in 1979. If current forecasts work out as expected, however, this near-miss is likely to have drastic consequences for the northwest coast of Alaska. This morning's northern Alaska forecast discussion from the National Weather Service Fairbanks office describes the potential impact of a very strong storm developing in the northern Pacific and headed across the Aleutians into the Bering Sea early this week (h/t Stu Ostro):
LOW NUMBER 2 IS REMARKABLY SIMILAR TO THE STORM THAT CAUSED MAJORThe top image shows the Arctic ice extent as of yesterday, November 5. The southern edge is well north of the northern coast of Alaska, leaving the Bering Sea, Norton Sound, and Chukchi Sea along Alaska's west coast ice-free.
COASTAL FLOODING ON THE NORTHWEST ALASKA COAST ON NOVEMBER 11 AND
12 IN 1974. THE ONLY DIFFERENCE OF ANY NOTE IS THAT THE 1974 STORM
CENTER CROSSED THE ALEUTIANS NEAR THE INTERNATIONAL DATE LINE.
THIS NOVEMBERS STORM IS DUE TO CROSS THE ALEUTIAN CHAIN AT ITS
WEST END ON TUESDAY MORNING. THIS NOVEMBERS STORM IS FORECAST TO
REACH BERING STRAIT WEDNESDAY MORNING. THE 1974 STORM ALSO ENDED
UP AT BERING STRAIT. IN A FEW WORDS...THE ORIGINS AND PATHS OF
THESE STORMS ARE SLIGHTLY DIFFERENT...BUT THEIR DESTINATIONS ARE
THE SAME.
THE OCEAN TIDES ALONG THE NORTHWEST ALASKA COAST THIS WEEK ARE AT
AVERAGE LEVELS. THE OCEAN TIDES AT THE TIME OF THE 1974 STORM WERE
AT MOST A FOOT OR TWO ABOVE THIS YEARS. HENCE...THIS IS A MINOR
FACTOR. IN THE 1974 STORM...THE WIND DRIVEN RISE IN SEA LEVEL WAS
CLOSE TO 10 FEET.
IN THE 1974 STORM THERE WAS CONSIDERABLE SEA ICE IN NORTON
SOUND. THE SOUTHEAST CHUKCHI SEA...FROM BERING STRAIT UP TO
BARROW INCLUDING KOTZEBUE SOUND...HAD EXTENSIVE ICE COVER DURING
THE 1974 STORM. THIS YEAR THERE IS ONLY A SMALL AREA OF SHORE ICE
IN EASTERN NORTON SOUND. ON THE CHUKCHI SEA COAST THERE IS ONLY A
NARROW STRETCH OF ICE...LESS THAN 10 MILES WIDE...FROM BERING
STRAIT TO POINT HOPE. KOTZEBUE SOUND IS 50 TO 70 PERCENT ICE
COVERED. ALL OF THIS MEANS IS THAT THERE WILL BE VERY LITTLE SHORE
ICE TO PROVIDE SOME PROTECTION TO THE COAST.
THE COASTAL FLOODING IN THE 1974 STORM BEGAN AT MID DAY IN NORTON
SOUND...AND TOWARD EVENING IN KOTZEBUE SOUND. IF LOW NUMBER 2
FOLLOWS THE SCRIPT OF THE FORECAST MODELS...THE COASTAL FLOODING
WITH THIS YEARS STORM WOULD BEGIN IN NORTON SOUND ON TUESDAY
EVENING...AND ALONG THE CHUKCHI SEA COAST FROM BERING STRAIT TO
POINT HOPE ON TUESDAY NIGHT.
THE LATEST GFS MODEL FORECASTS INDICATE A SHARP CHANGE IN THE
WIND OVER NORTON SOUND ON WEDNESDAY MORNING...SHIFTING FROM
SOUTHEAST TUESDAY NIGHT TO SOUTHWEST WEDNESDAY MORNING. IF THE
OUTCOME ON WEDNESDAY FOLLOWS THIS FORECAST...THERE WOULD BE
ADDITIONAL COASTAL FLOODING ON THE YUKON DELTA AND IN EASTERN
NORTON SOUND.
LOW NUMBER 2 IS GOING TO BE A DANGEROUS STORM.
The second image shows an output weather map from the main U.S. global forecast model, the GFS. It is a 60-hour forecast for 6 am GMT on Wednesday, November 9. A very strong storm with a minimum pressure of 940 mb is centered in the Bering Sea, moving toward the Bering Strait and pounding the west coast of Alaska with dangerously high winds.
The sea ice extent doesn't need to set a new record in order to have serious consequences.
Posts
