Winter Will Be a Major Factor in the Ukraine War, Officials Say

WASHINGTON — Senior Biden administration officials say Russia’s military operations in Ukraine will remain stalled well into next year, as recent Ukrainian advances upset Moscow’s hopes to seize more territory in areas that President Vladimir V. Putin has tried to portray as historically part of Russia.

While the officials say that Moscow is likely to continue to attack Ukrainian troops, bases, infrastructure and the electrical grid, the coming winter is expected to bring a slowdown in military advances on both sides.

In a major setback in the war, the Kremlin announced on Friday that its forces had withdrawn from the strategic city of Kherson in southern Ukraine and relocated across the Dnipro River. U.S. officials believe that Russia’s decision to pull out of the city was based in part on concerns that its soldiers would be penned in and cut off from supplies as winter set in.

Ukrainian troops had destroyed or damaged all but one bridge into the city, limiting Russia’s ability to resupply its 20,000 to 30,000 troops, many of whom Moscow sent to the front in the past weeks with little to no training, a NATO official said.

American officials had estimated that the Russian retreat would take two weeks, but the Russian Defense Ministry said on Friday that the withdrawal was complete, and residents said the remaining bridge across the Dnipro to the city had been destroyed.

The winter pause could last as long as six months. Rain and soft ground in late November will slow the movements of both militaries. Then, as temperatures fall and the ground freezes, it will be easier for tanks and trucks to move. But the possibility of heavy snows and even colder weather could make it difficult for the poorly equipped Russian army to mount any new offensive.

“You’re already seeing the sloppy weather in Ukraine slow things down a little bit,” Colin H. Kahl, the under secretary of defense for policy, told reporters this past week. “It’s getting really muddy, which makes it hard to do large-scale offensives.”

With a weather-enforced pause in major military movements, the war will enter a new phase. Russia will likely intensify its attacks on infrastructure to terrorize Ukrainians, U.S. officials said. And Ukraine could step up a covert campaign designed to show that it can strike back even on Russian soil, according to analysts.

“Ukrainians look like they’re going to continue to press forward with sabotage and subversion attacks on Russian lines,” said Seth G. Jones, senior vice president at the Center for Strategic and International Studies. “These are targeted assassinations and just general sabotage against Russian-controlled areas inside Ukraine.”

Biden administration officials say that it is imperative to use the winter slowdown to rebuild Ukraine’s defensive and offensive weapons supply.

On Thursday, the Pentagon announced another $400 million in weapons, including mobile short-range Avenger air defense vehicles that fire Stinger missiles.

But officials in Kyiv say they will need more air defense systems, beyond the SA-11s and S-300s Ukraine’s military already has, which have kept Russian pilots largely out of Ukrainian airspace, and more tanks and even fighter jets to retake areas that Mr. Putin has illegally annexed over the past nine months of war.

During the looming pause, both sides will also retrain troops and gear up for a renewed push in February, military analysts said.

Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff and Mr. Biden’s top military adviser, said this week that the coming cold was an opportunity for both sides to consider peace talks. The war has already left more than 100,000 Russian troops dead or wounded, he said, adding that Ukraine has probably suffered a similar number of casualties.

The Kremlin would certainly like to see a cease-fire put into place in the coming months to replenish its military and strengthen its position on the ground, two Russia military analysts wrote in a Royal United Services Institute analysis last week. The analysts, Jack Watling and Nick Reynolds, said the Russian government was encouraging Ukraine’s international partners to pressure the government in Kyiv into negotiating a truce.

But “a cease-fire is tactically advantageous for Russia in stabilizing its control over the occupied territories, and fails to offer the prospect of the Kremlin reducing its aim of subjugating Ukraine or halting its coercive energy diplomacy against Western Europe,” Mr. Watling and Mr. Reynolds wrote.

And several military analysts say it is not in Ukraine’s interests to let up this winter, particularly as Russia continues targeting civilian infrastructure and the electrical grid. Ukrainian officials say they believe Russia is also likely to attack the country’s water supply systems.

But Biden administration officials said there could be a limit to how long Russia can continue its campaign to destroy infrastructure as its supplies of long-range precision-guided missiles dwindle. Moscow has used Iranian-made attack drones to make up for the shortfall, but it is not clear how many more it can acquire.

American intelligence does not have a precise estimate of what remains of Russia’s precision-guided munition stocks, including cruise missiles and drones. But Russia’s industrial base has struggled to build additional weapons because of problems at factories and a shortage of supplies caused by Western sanctions.

With the equipment problems and an infusion of newly drafted soldiers who will need to be trained, Russia is most likely hoping to use a winter pause to rebuild, American officials said.

“For Ukraine, winter conditions will make the logistics for conventional operations to reclaim territory more difficult, while the lack of vegetation and other cover will make advances with limited armor risky,” the Royal Institute analysts wrote. “For Russia, with demoralized forces and poorly prepared positions, the winter is likely to see a further slump in morale and significant casualties from exposure injuries.”

Mr. Kahl, the Defense Department senior official, said “we should expect both sides to be exchanging artillery fire.” He added, “The Russians seem intent on continuing to lob cruise missiles and Iranian drones at Ukrainian civilian infrastructure.”

Moscow may keep that up, he said, “so the war will continue even if the intensity of it is somewhat altered.”