Facts About the Arctic in May 2021

It’s May Day 2021, and just for a change we’re going to start the month off with a pretty picture!

Parts of the Laptev Sea are starting to look distinctly “warm” in the infra-red. Here’s a “false colour” image taken by the Terra satellite during a gap in the clouds:

We have reached the time of year when the SMOS “thin ice thickness” readings start being affected by surface melt, but let’s take a look anyway:

That area of the Laptev certainly appears to be either thin or melting.

Meanwhile on the Canadian side of the Arctic the fast ice off the Mackenzie Delta is starting to get damp, even though the river itself still looks to be fairly well frozen:

It will also be interesting to follow the progress of this large floe as it heads towards oblivion through the Fram Strait:

[Edit – May 2nd]

The final reprocessed CryoSat-2/SMOS Arctic sea ice thickness map of the 2020/21 season has just been published by AWI:

Here too is the resulting volume graph:

This reveals a maximum volume of 18060.5 km³ on April 7th. That is well below all other maxima in the CS2 record going back to 2010, including 2011/12 which went on to produce the lowest minimum extent in the satellite era.

[Edit – May 5th]

The PIOMAS gridded thickness data for April has been released, and Wipneus has worked his magic. Of particular interest this time around is Fram Strait volume export:

The peak is lower than last year, but export has been continuous throughout April, with not even a single negative day. Moving on here’s the thickness map for April 30th:

followed by the volume and volume anomaly graphs:

Modelled volume is sixth lowest for the date, but effectively in a “statistical tie” for second lowest, a long way behind 2017.

[Edit – May 6th]

The National Snow and Ice Data Center have just published the latest edition of Arctic Sea Ice News – “A step in our spring“:

The spring decline in Arctic sea ice extent continued at varying rates through the month of April, highlighted by a mid-month pause. Above average air temperatures and low sea level pressure dominated on the Atlantic side of the Arctic, while near average conditions ruled elsewhere.

Arctic sea ice extent averaged for April 2021 was 13.84 million square kilometers (5.34 million square miles). This was 410,000 square kilometers (158,000 square miles) above the record low for the month set in 2019 and 850,000 square kilometers (328,000 square miles) below the 1981 to 2010 average. The average extent for the month ranks sixth lowest in the passive microwave satellite record. Extent was notably low in the Barents and Bering Seas as well as the Labrador Sea. Elsewhere, extent was close to or somewhat below average (Figure 1). The largest ice loss during April was in the Sea of Okhotsk and the Labrador Sea, with smaller losses along the southern edge of the Bering Sea, and in the eastern Barents Sea near the coast of Novaya Zemlya.

The article also includes an update on Arctic sea ice age:

The sea ice continues to be far younger, and thus thinner, than in the 1980s. There is little change in the age distribution from last year. At the end of the ice growth season in mid-March, 73.3 percent of the Arctic Ocean domain was covered by first-year ice, while 3.5 percent was covered by ice 4+ years old. This compares to 70.6 percent and 4.4 percent respectively in March 2020. In March 1985, near the beginning of the ice age record, the Arctic Ocean region was comprised of nearly equal amounts of first-year ice (39.3 percent) and 4+ year-old ice (30.6 percent).

[Edit – May 7th]

The snow has gone from the upper Mackenzie valley, and the river ice has also gone in a few places:

[Edit – May 8th]

The “large floe” mentioned at the top of the page has managed to stay intact as those around it have disintegrated on their way through the Fram Strait. Here’s a somewhat cloudy animation showing the floe’s movement from day to day:

[Edit – May 10th]

The Polar Science Center has released the April PIOMAS data. No surprises with the volume graph, but their anomaly maps are always of interest, and these days they include comparisons with CryoSat-2:

PIOMAS Ice Thickness Anomaly for April 2021 relative to 2011-2020.
CryoSat-2 (AWI) multi-sensor Sea  Ice Thickness Anomaly for April of 2021 relative to 2011-2020 (version 2.3 prelim)
Time Series of CryoSat-2  multi-sensor analysis (AWI/ESA)  and PIOMAS Sea  Ice Volume Anomaly for April.

The divergence between PIOMAS and CS2 total volume is apparent once again this month. Despite that the anomaly maps are broadly similar, with positive anomalies on the Siberian side of the Arctic versus negative ones on the Canadian side. There is one obvious difference of opinion however. The majority of the Beaufort Sea is blue for CryoSat-2 but red for PIOMAS.

[Edit – May 11th]

The “big block” we’ve been watching on its journey through the Fram Strait has started breaking up into smaller pieces under a veil of cloud:

[Edit – May 14th]

This morning there’s a fairly clear view from the NOAA-20 satellite of the disintegration of the sea ice cover in the Chukchi Sea and thereabouts:

Here’s the current high resolution AMSR2 sea ice area graph for the Chukchi Sea

Meanwhile over on the North Atlantic side of the Arctic, sea ice area in the Laptev Sea is now second lowest in the AMSR2 era, behind 2020:

[Edit – May 15th]

This is the time of year when snow cover over Canada and Siberia becomes very important to the overall albedo of the Arctic. The GFS is also forecasting a persistent anticyclone over the Arctic:

It’s due to start in 3 days, so quite possibly it will verify in the “real world”, which will not be good for the ice since insolation is increasing quickly as midsummer’s day approaches, and high pressure implies few clouds. From now until early August the Arctic receives more energy from the sun than equatorial regions:

Northern Hemisphere snow extent is already very low for the time of year:

Run the Climate Reanalyzer animation to see what’s predicted to happens to the remaining snow cover over the land surrounding the Arctic Ocean over the next few days.

Watch this space!

3 thoughts on “Facts About the Arctic in May 2021

  1. Further to the snow melt in the Mackenzie valley I have been informed via the Arctic Sea Ice Forum that Fort Simpson has been flooded this year:


    Water levels in Fort Simpson, N.W.T., are rising to new extremes.

    Local resident Brandon Buggins told CBC on Friday that the water levels are the highest they have been this season, rising above 16 meters.

    Last Friday, the Liard River broke, triggering a local state of emergency, and eventually, mandatory evacuation for those who live on the island, which rests on low ground. Mandatory evacuation was triggered at 14 meters.

    Over 700 people have been displaced and evacuated to higher ground or to other N.W.T., communities.

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