Why spring storms mess up the roads

Stearns County plow
The plows were out in Stearns County Thursday morning, April 11, 2013, as a late-season snow storm pushed through Minnesota. Roads conditions and visibility are drastically reduced in parts of west of St. Cloud.
MPR Photo/Conrad Wilson

There's a scientific explanation for why spring storms make such a mess out of the roads.

According to the Minnesota Department of Transportation, the ground is above freezing. As the snow hits the pavement, its melts on contact. But so much snow fell that it accumulated and covered, even insulated, that melted layer.

As plows removed the snow and exposed the melted layer, the blowing cold air quickly froze it. That's what has quickly created the icy conditions.

T.J. Melcher, a spokesperson with MnDOT in Willmar, said the time of year makes this particular storm difficult.

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"When you get a snow storm like this in the middle of winter, it's easy enough to clear out the snow and the ground temperatures are a lot lower so it doesn't allow that snow to turn to icy right away," Melcher said. "On top of that, the amount of snow events we've had this year, our snow plow drivers have been working consistently throughout the winter season so they're obviously getting fatigued."

Melcher said snow plow drivers are having an easier time clearing roads now that the sun has come up.

He said the roads are improving, but still difficult in the west-central and southwestern parts of the state.

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MnDOT: Statewide road conditions
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