Introduction
On July 26, 2022 sea ice was seen in the Bering Strait, which is unusual for this time of year. The cause of this anomaly is a record deep low pressure system that arrived in the area on July 17, 2022. As a result of this record low pressure, winds around the Bering Strait and the Siberian Coastal Current were enhanced. A combination of wind and currents flowing towards the Bering Strait, plus slightly anomalous cold sea surface temperatures (SST) and cooler air temperatures, prevented sea ice melting and instead caused the sea ice pack to drift towards the Bering Strait. On August 7, 2022, another low pressure system sat over the Strait, pushing the sea ice into the Bering Sea.
Images from July 13 to August 10 of the northeast Russian Coast with Diomede in the bottom right.
Image 1: July 13 - Land and no sea ice (ocean is black)
Image 2: July 28 - Sea ice pack is visible through the clouds
Image 3: Aug 2 - Sea ice pack is rounding the corner into the Bering Strait
Image 4: Aug 14 - Sea ice in the Bering Sea with clouds on the right hand side.
True Color Satellite imagery from July 13, 2022 to August 14, 2022 courtesy of Sentinel Hub EO Browser .
July 18 - Record Low Pressure
Rick Thoman, climatologist with the Alaska Center for Climate Assessment and Policy, noted on July 13 that a deep low pressure system might develop in the Bering Strait region later that week. The record breaking deep low pressure did in fact enter the Bering Strait on July 18, before moving eastward and weakening. As a result of the strong pressure gradient, wind speeds and the Siberian coastal current increased, which encouraged sea ice movement along the northeast Russian coast. Due to the anomalously cold SSTs and the cold air from the low pressure system, sea ice made it to the Bering Strait without melting too quickly.
On July 13 it is first noted by Climatologist Rick Thoman that a record deep closed low was possible near the Bering Strait.
Rick Thoman on Twitter: "Nerd alert: Wx models bringing a deep closed low aloft near/onto the Chukotka Peninsula over the weekend: here ECWMF with 512dm center at 67.5N/178W. H/T @WorldClimateSvc did the ERA5 analysis showing would be the lowest post-1950 July 500hPa height in this part of the #Arctic. pic.twitter.com/dearlKnpjw / Twitter"
The record low pressure system reached the Bering Strait on July 18 before moving eastward and weakening.
Brian Brettschneider on Twitter: "Just a sub-516 dm low over the Bering Straight. Nome with a July record lot 500 mb height (H/T @AlaskaWx) pic.twitter.com/IAHEwRlXjz / Twitter"
The record cold, closed low pressure system over the Seward Peninsula.
Rick Thoman on Twitter: "Tuesday morning Suomi NPP "truecolor" image courtesy @uafgina showing the record (since 1950) deep, cold closed low, aka "spinny thing", centered over the Seward Peninsula between Nome and Kotzebue. #akwx @Climatologist49 @CIMSS_Satellite @UAFGI pic.twitter.com/tFsqJ8sJJM / Twitter"
The placement of the record deep low pressure resulted in strong winds that enhanced the Siberian Coastal Current. The Siberian Coastal Current is found along the northeast coast of Russia and when present, brings fresh, cold water to the southeast. Downwelling favorable winds enhance this current (Weingartner et. al., 1999) and in some cases it may reach the Bering Strait.
As these winds were also sufficiently strong, that can reverse the normally northward flow in the Bering Strait. Reversals have a typical duration of 1 - 10 days (Weingartner et. al., 1999), and in our case this appears to have occured twice in one months time.
As compared with 1990-2020 climate normals, SSTs were anomalously cold.
Rick Thoman on Twitter: "Sea surface temperatures across the Gulf of Alaska very close to average for mid-July in @NOAA_ESRL data. Western Bering Sea #sst still above average, but central/eastern Bering & southern Chukchi mixed. Beaufort Sea still ice dominated. #akwx #Arctic @Climatologist49 @UAFOceans pic.twitter.com/ugUjmq5RKh / Twitter"
Along the northern coast of Russia and in the Bering Sea, SSTs remained anomalously cold.
Rick Thoman on Twitter: "Ocean surface temperature in the Bering Sea have developed a fairly dramatic spilt, with the western Bering Sea #sst far above 1991-2020 average but eastern Bering Sea cooler than average in @NOAA_ESRL data. Gulf of Alaska near average. #akwx #Arctic @Climatologist49 @UAFOceans pic.twitter.com/ZWxJAUJBlT / Twitter"
As a result of the record deep low pressure system, air temperatures dropped as well. This resulted in snow on Little Diomede, which is not common in July.
Rick Thoman on Twitter: "July #snow in the Bering Strait: flurries on Iŋaliq (Little Diomede), Alaska Sunday evening, and then a gorgeous Monday early morning view looking west to Big Diomede, Russia. Snow in July is unusual. Photo by F. Ozenna & shared with permission. #akwx @Climatologist49 @brdemuth pic.twitter.com/6UubAruUab / Twitter"
This record low pressure enhanced the Siberian Coastal Current and winds on the northeast side of Russia near the Bering Strait. This movement plus slightly anomalously cold SST and cooler air temperatures haulted sea ice melting and instead brought the sea ice pack towards the Bering Strait.
The result was the movement of the sea ice pack 125 nautical miles to the east and into the Bering Strait less than a week after the record low pressure passed over the region. The map below shows where the sea ice was on July 18th prior to the record low pressure and then the result is on the right from July 28th, where the sea ice makes it into the Bering Strait!
Sea Ice change. Left map is 7/18. Right map is 7/26.
August 8 - Ice in Bering Sea
A second Low pushing the sea ice from the Bering Strait into the Bering Sea.
Note the surface low pressure approaching the Bering Strait with near gale force winds. The sea ice edge is noted by the blue circles. This low pressure arrived the morning of Aug 7th. Though not as deep or record breaking as the one in July, with the ice pack already in position, the increased pressure gradient and downwelling, once again enhanced the Siberian Coastal Current to encourage the movement of the ice into the Bering Strait and then into the Bering Sea.
This low pressure and its impact was noted by the Alaska Sea Ice programs forecasters. The forecast on Aug 1 valid on Aug 6 stated:
"...Some ice will likely linger along the Russian Coast due to local currents. Later in the week the ice may advance 5 to 15 nautical miles southeast due to the influence of the low later in the week." - Carson
The result was the movement of the sea ice pack into the Bering Sea! The map below shows where the sea ice was on August 7th (left) and as a result of the low pressure on August 8th (right). This ice didn't have as far to move as the previous low pressure, as it was already in the Bering Strait. The main ice pack is the orange and red colors. Green here is very open ice.
Sea Ice Movement. August 7th, 2022 (left). August 8th, 2022 (right).
Conclusion
In conclusion, this anomaly occured due to a number of atmospheric and oceanic conditions. Annomously cold SST anomaly, possibly due to an increase in the amount of fresh, cold water entering the Siberian Coastal Current, a record deep low pressure which enhanced the Siberian coastal current as the wind and current directions aligned, increased wind speeds, and dropped air temperatures.
Note the cold color locations
Rick Thoman on Twitter: "Nerd alert: For the northern Bering Sea/Bering Strait region, July average temperature of the lower half of atmosphere (roughly surface to 18000 ft/5400m) was 3rd lowest since 1949. Only 1965 & 1970 cooler. Data from NCEP/NCAR reanalysis. Graphic courtesy @Climatologist49 #akwx pic.twitter.com/cp2ggUwcyy / Twitter"
Unfortunately, just because this anomalous event happened leading to sea ice in the Bering Sea, does not mean the overall Arctic Sea Ice isn't being severely impacted by climate change.
Disappearing Arctic sea ice
Future Work
Taking a look back at the archived data from the Alaska Sea Ice Program, when do similar events occur where the sea ice makes it into the Bering Strait and possibly into the Bering Sea? Does this have a connection to La Niña?
Take a look at the full sea ice dataset here
Citations
Rick Thoman - climatologist with the Alaska Center for Climate Assessment and Policy (ACCAP)
Brian Brettschneider - climatologist with the National Weather Service in Anchorage, AK
Weingartner, T. J., Danielson, S., Sasaki, Y., Pavlov, V., and Kulakov, M. (1999). The siberian coastal current: a wind- and buoyancy-forced Arctic coastal current. J. Geophys. Res. Ocean. 104, 29697–29713. doi: 10.1029/1999JC900161
International Arctic Research Center (IARC)
