The problem is that driver education classes typically gloss over what makes winter driving different and how to avoid and handle skids, said Tim O’Neil, the founder of Team O’Neil, a rally-driving school in Dalton, N.H., that also teaches winter driving.

That’s why even people who have been driving for decades can make crucial mistakes on snowy roads, said Mark Cox, the director of the Bridgestone Winter Driving School in Steamboat Springs, Colo.

“We see a lot of people from all over the country who have grown up in the Snow Belt and have years and years of driving experience and in reality have just been lucky because their technique leaves a lot to be desired,” Mr. Cox said.

The biggest problem is speed, and not knowing it will take much longer to stop, experts say. Here’s some other advice to avoid slip-sliding away.

Some snow is more slippery

The amount of grip available on snow can change sharply depending on the temperatures, said James H. Lever, a researcher at the Army’s Cold Regions Research and Engineering Laboratory in Hanover, N.H.

Warm snow is weaker and gives way more easily, so tires have a harder time getting a good grip, he said.

“As temperatures warm up, it gets more slippery. It is a big effect,” he said. For example, when the air is 30 degrees Fahrenheit, packed snow is about five times more slick than it is at zero degrees.

Researchers say when a tire begins to slide across the snow at higher temperatures it is more likely to melt the snow. That water then acts as a lubricant.

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Christopher Jensen is a freelance writer for The New York Times and New Hampshire Public Radio, Staffer at InDepthNH.org.