Science of snow: Meteorologist explains perils of winter drivingJan 17, 2022 04:49AM ● By Editor
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By Gordon Severson of KARE 11 News - January 17, 2022
Here in Minnesota, we've seen it all.
Snow, ice and wind: It's a way of life in winter, but sometimes one inch of snow is enough to send hundreds of cars into the ditch. At other times, you won’t see a single car in the ditch. Why is that?
"When we're talking about snow, wind is probably the biggest factor,” National Weather Service meteorologist Nick Carletta said.
Like the wind we saw Friday morning.
Carletta says it wasn't super fast, but just fast enough to cause a few problems.
"The thing that makes them shut down roads is actually blizzard conditions caused by high winds. When they plow a road and it is completely snow covered within like, five to 10 minutes, they just can't keep a road open because it blows right back in,” Carletta said.
And strong wind can also push salt off the road.
"We had a weather event just like that this past month where we had high winds coming in and it was really challenging for MnDOT,” Carletta said.
So, wind is a big deal; how about temperature?
"Our warm conditions from the past few days had produced a fair amount of snow melt which created a little bit more of a wet-road scenario. Then the cold temperatures overnight would lead to a refreeze. And then especially if you can throw on a nice layer of snow on top of that, that could lead to some pretty slick conditions,” Carletta said.
If you put those two factors together — wind and temperature — Carletta says you have the making of a very serious snow event.
"If I had to create the most serious snow event, it would be a giant ice storm. You'd get something that would essentially be rain, but then at the surface you'd be maybe right at, like, 30 to 31 degrees, and you could just accumulate nothing but super thick ice. These ice storms are typically more common in other parts of the country than they are here, but that's where you cause the most havoc. And the other one would just be a major blizzard — having snow falling, along with 40-plus-mile-per-hour winds, that just cover everything up right away,” Carletta said.
The cherry on top of this crazy blizzard or ice storm would be the timing of it all.
Carletta says the first few snow events of the season are always the worst when it comes to crashes and spin outs.
"Minnesotans are generally quite above average compared to the rest of the country with driving in snow, but if you haven't dealt with it for a couple of months, it can take a little bit of time to remember how to do it,” Carletta said.
So, we've got wind, temperature, and timing, but there's a fourth factor: human behavior.
If we don’t take a snow event seriously, like a small 1- or 2-inch dusting, those snow events can often cause more accidents than a blizzard with a foot of snow.
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