Early ice melt in Canadian Arctic

Sea Ice Testing New Record Lows as Heat Wave Invades Northwest Territories

Robertscribbler,

12 May, 2015

For 2015, it looks as if Arctic sea ice is sitting in some rather hot water.

For from the Chukchi to the Beaufort to Hudson Bay to Baffin Bay and on into the Kara, the edge region of the Arctic Ocean is feeling a very strong melt pressure during early May of 2015. And, according to 7-10 day forecasts, that melt pressure will only intensify. As a result, we could see new record lows for Arctic sea ice extent over the next few days.

Early Melt for the Chukchi and Beaufort

Arctic warming is now particularly intense along a broad region running from coastal Alaska through to the Mackenzie Delta and on into the northwestern portion of the Canadian Archipelago. It’s an area that typically waits until at least June to melt. But, this year, sea ice recession, break-up and opening of large polynyas for this far northern area is occurring almost in tandem with melt in more southerly regions like Hudson Bay.

For both the Chukchi and Beaufort Seas are continuing an early melt that began in March and has proceeded on to this day.

(Chukchi Sea north of the Bering Strait showing early melt and break-up on May 11, 2015. Image source: LANCE-MODIS.)

In the image above we can see the MODIS satellite shot for the Chukchi Sea region on May 11, 2015. Note both the fractured nature of sea ice, the ice edge retreat that has already progressed well past the Bering Strait (a retreat far beyond a steadily retreating average extent line), and the very large polynya advancing into the Chukchi along the northern edge of Alaska.

It’s a melt that has been spurred by powerful southerly air flows and wind-driven currents issuing from the Bering Sea and Pacific Ocean to the south. There, a cluster of storms continued to back up and deflect northward toward the Arctic as powerful high pressure ridges remained entrenched over a pool of record warm water in the Northwestern Pacific.

(Beaufort Sea ice near Mackenzie Delta showing advanced signs of break-up on May 11 of 2015. Image source: LANCE-MODIS.)

These same ridges are driving warm air up over the western region of the North American Continent. This flood of warm air has persistently invaded the Northwest Territory of Canada, forcing an early melt of the Mackenzie River. The heat has also frequently invaded the southern Beaufort Sea. The result is that the sea ice there is greatly fractured and that a large polynya dominates a wide area bordering Alaska, the Mackenzie Delta, and the Canadian Archipelago.

This polynya extends about 650 miles, has a width ranging from 15 to 80 miles and stretches 250 miles into the Canadian Archipelago between the Northwest Territory mainland and Banks and Victoria Islands. Many hundreds of miles to the north and east of this large polynya, is a mess of fractured ice rippling out through the Beaufort Sea. A massive disassociated ice flow that belies great general weakness for sea ice in the region.

Risk of Rapid Melt

As melt season progresses, these wide, dark areas of open ocean will serve to trap the radiant heat of 24 hour sunlight. The expansive stretches will generate swells that tear away at the surrounding ice. Already fractured ice flows will retain far less integrity than the contiguous, and far thicker, ice of years past. These combined factors set up conditions that can greatly enhance and speed the rate of ice loss as the spring advances into summer.

(NSIDC shows sea ice extent at second lowest on record for May 11, 2015. Rate of decline implies a plunge toward the 2006 record low line. Image source: NSIDC.)

This risk is particularly relevant when we consider that sea ice extent measures were at record low values throughout about half of March and for brief periods during early April. Currently, sea ice extent is at its second lowest level on record. A value that is now rapidly plunging toward the record low line set in 2006. Any continuation of the current rate of decline would bring the extent measure into new record low territory over the next few days.

A weekly continuation of this trend could push extent values far into record low territory, further worsening sea ice prospects for the broader 2015 melt season.

(7 day forecast shows Arctic heatwave building through the Northwest Territory. Image source: Climate Reanalyzer.)

To this point, 7 day forecasts predict a massive warm-up building over Alaska and the Northwest Territory through May 19th. Temperatures over land in this area are expected to build into the 70s and low 80s. This extreme warmth, in the range of 10-20 Celsius above average (18 to 36 Fahrenheit), will stretch all the way to Arctic Ocean shores off the back of a ridiculously resilient ridge in the Jet Stream. A ridge that has persisted, off and on, for much of the past three years. Above freezing temps will pulse out from the ridge to cover most of the Chukchi and almost all of the Beaufort — adding melt pressure to already fragile sea ice conditions for that region.

Links:

LANCE-MODIS

NSIDC

Climate Reanalyzer