Early ice break-up in Alaska

Barrow Sea Ice Break-up: Dark Open Water In Late April

(Image source: Barrow Sea Ice Cam.)

Robertscribbler,

30 April, 2013

The warming trend that we provided predictive analysis for yesterday has barely even begun and we already have visible dark, open water off Point Barrow, Alaska as of late Tuesday evening on April 29.  A large polynya that had opened up off the northern Alaskan coast has now extended well past Barrow and landward toward the near-shore waters. By late evening, the open water had invaded to within about 200 yards of shore along and past the Point Barrow coastline.

In broader summary, the open water polynya stretches from Cape Lisburne to past Point Barrow and measures between 20 and 50 miles in width. General trends show this large polynya continuing to expand northward into the Chukchi Sea, a motion that is likely to continue for at least the next few days.

Some cooling will likely return after the currently building Arctic heatwave, but it is questionable if it will be enough to result in a refreeze given the prevailing and much warmer than usual conditions.

Sea ice break-up at Point Barrow typically begins in mid-to-late June. It often involves both the formation of open water offshore as well as sea ice motion near-shore. Though the polynya removed ice from the off-shore waters of Point Barrow today, the near-shore ice still remains grounded, so this admittedly impressive event cannot technically be considered a break-up. That said, it appears that we are seeing a very early initiation of melt conditions for the Barrow region.

With warmer weather settling in, heat stresses to the local and regional sea ice will likely continue to ramp up. So, in other words, this early season melt event has only just begun.

(Large polynya extending from Cape Lisburne to about 80 miles past Point Barrow on April 28. The polynya continued to enlarge even as it invaded the near-shore regions of Point Barrow on April 29th. Image source: LANCE-MODIS.)

Links:

Barrow Sea Ice Cam

LANCE-MODIS