The Washington PostDemocracy Dies in Darkness

Ukraine faces severe cold blast as it fights Russian invasion

The freezing temperatures come at a time when hundreds of thousands of Ukrainians are without electricity and could affect troop movement

A man walks through a checkpoint in heavy snow on March 7 in Lviv, Ukraine. (Dan Kitwood/Getty Images)
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As Russian troops continue to occupy Ukraine for a third week, temperatures in the region are expected to plummet near their coldest levels so far this winter season — potentially affecting troop and refugee movements, military and geography experts say.

A strong blocking high-pressure system has developed over western and northern Europe, opening a passageway for very frigid Arctic air to enter northern Asia and Eastern Europe. The polar outbreak could bring daytime temperatures 18 to 22 degrees (10 to 12 Celsius) below normal in eastern Ukraine on Thursday and Friday, and 9 to 13 degrees (5 to 7 Celsius) below normal in the western part of the country.

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It’s projected to be the most frigid weather the country has seen in weeks; the only colder weather occurred in late December and for a time in mid- and late January amid an otherwise very mild winter.

By Friday morning, much of Ukraine could have temperatures around 14 degrees (minus-10 Celsius). A wind chill from easterly gusts could make the air feel as cold as minus-4 degrees (minus-20 Celsius). Parts of northeastern Ukraine could also get up to 4 inches (more than 12 centimeters) of snow through Friday.

As a reinforcing shot of Arctic air arrives from Russia over the weekend, temperatures could fall below zero degrees Fahrenheit in northeast Ukraine. The Arctic outbreak and cold temperatures will persist through mid-March, when the blocking high will begin to collapse.

The below-freezing temperatures come at a time when hundreds of thousands of Ukrainians are without electricity and gas. As of Monday, Ukraine’s Ministry of Energy reported around 650,000 people do not have electricity. At least 130,000 people in the east, north and south are left without their natural gas supply, which is often used for cooking and heating during harsh cold temperatures. More than 1.7 million Ukrainians have fled the country so far.

Colder-than-normal air has hovered over Ukraine since Monday, with temperatures averaging 4 to 8 degrees (2 to 4.5 Celsius) below normal.

“Cold weather indeed affected civilians, who [were] trying to flee the war zone,” Tatiana Adamenko, head of Agrometeorological Department of the Hydrometeorological center of Ukraine in Kyiv, wrote in an email. Adamenko corresponded with The Washington Post through Inbal Becker-Reshef, University of Maryland professor and program director of NASA Harvest, which collaborates with the Ukrainian hydrometeorological center for crop forecasting.

The official Ukrainian Hydrometeorological Center website has been unresponsive for several days. Adamenko said standard meteorological information is still coming in and is saved on its server, but only from the stations that are not being occupied by the enemy forces. She said sometimes the center uses data from the German meteorological service. However, weather information for the Ukrainian army is being provided by the military hydrometeorological service, with which she does not have a connection.

“Situation is very not safe here,” wrote Adamenko, who reported an air alarm was going off at the time.

This week’s extreme cold comes in stark contrast to unusually warm temperatures in February. Data from 17 Ukrainian ground weather stations indicated temperatures in February were several degrees above normal averaged over the month. Many weather stations had interrupted service near the end of February, but satellite data also shows above-average temperatures into March.

“It has been unusually warm in Ukraine. They had a period with about 5 degrees [Celsius] plus [above average] for a few consecutive days over February. That is unusual because usually it’s below 0 during this [time of the] year,” said Daniel Müller, a geographer and agricultural economist at the Leibniz Institute of Agricultural Development in Transition Economies. “This indeed contributed to an early thawing of the soils that might have created problems for the heavy armor of the Russians."

Warmer February temperatures have favored an earlier onset — potentially two weeks earlier than normal, said Müller — of a regional mud season called rasputitsa. Rasputitsa occurs twice a year: once in autumn as the rain falls and once in the spring as the snow melts. During rasputitsa, unpaved roads become muddy, sticky messes that can slow down even large tanks.

“There’s this clay underneath the topsoil, which prevents the water from draining further down, and that’s why sort of the humidity accumulates in the upper soil layers. That’s why this becomes extremely muddy,” Müller said. “Entire regions in southern Belarus, southern European Russia are famous for these mud conditions, this rasputitsa, in spring and autumn.”

In Ukraine, Müller said rasputitsa occurs in the northern region in the mixed coniferous broad-leaved forest zone such as in the Polesian lowlands and in the forest steppe zone, where Kyiv is located. He said it doesn’t typically occur in the drier steppe and black soil region in the south, such as near Crimea.

“Russians have been stymied in the north and northeast and seem to be making progress in the south. Is that related to weather and mud? … I don’t know,” said Col. Mark Cancian, who spent over three decades in the U.S. Marine Corps and is currently a senior adviser with the Center for Strategic and International Studies International Security Program.

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However, Cancian said the weather so far “certainly has favored the defense, particularly around Kyiv” to some degree. The muddy conditions seem to have kept military vehicles off the terrain and funneled onto roads.

“Columns [of vehicles] tend to get channeled onto the roads, and we’re seeing that,” Cancian said. “When that happens, then it favors the defense because they don’t have to defend a broad front. They can focus their energies on relatively narrow fronts, the roads. So that helps the Ukrainians.”

Adamenko said low clouds have also caused enemy aircraft to fly at a low altitude, becoming a target for Ukrainian air defenses.

Given the mud season, the timing of the initial invasion was unusual.

“In retrospective, I would have guessed they come in earlier because really harsh winter conditions are best for such an attack because then the heavy vehicles can move anywhere,” Müller said. “Temperatures have been far above the average so maybe they haven’t expected that.”

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Cancian said typically campaign season in Russia starts after the ground has dried out, which is usually in April. He thinks Russian President Vladimir Putin proceeded to attack because “Putin thought he was going to win in a couple of days … he didn’t think he was going to be fighting in the mud, and he thought it would be all over by now.”

With the upcoming Arctic blast, it is unclear how terrain and troop or refugee movement may change soon.

Forecasts project mostly below-average temperatures for at least one week, with the most extreme cold Thursday through Monday. Kyiv’s temperatures could plummet to 16 degrees (minus-9 Celsius) Saturday while Kharkiv’s could dip as low as minus-2 (minus-19 Celsius).

Some light snow is forecast east of Kyiv on Thursday and Friday, but it is unclear how deep it may pack over soils for troop movement. So far, snow this season has been below average and unstable, Adamenko said.

Beyond the Arctic blast, spring rains will be the next concern for military movements. The rains, which typically occur around mid-March to early April, can add to the muddy terrain.

“It is now very relevant how early the rains will start,” Müller said. “Once the spring rains come, which usually come [in the middle or end] of March or early April, then you know this mud thing would really become impassable basically completely and for heavy vehicles.”

Then once the ground dries out, Cancian said the mud advantage may no longer be a factor for the Ukrainians. “Weather makes it easier for an attacker to maneuver when the ground dries out,” he said.