The Ottumwa Courier

January 14, 2014

Where did Tuesday's ice come from?

Courier staff writer

---- — OTTUMWA — Tuesday’s school closures and delays came as a surprise to many in southeast Iowa.

There was snow, but nothing new. Official measurements showed just four-hundredths of an inch of mist overnight. But there was the ice, glazing roadways to the point that hills were a challenge.

But the confounding thing, the thing that threw even experienced observers, was that the air temperatures when the ice formed were never below freezing. They were in the mid-30s.

What the heck happened?

Kurt Kotenberg, a meteorologist with the National Weather Service in Des Moines, said southeast Iowa saw an unusual confluence of events. The air was warm enough, but the ground was still frozen. That’s not uncommon at this time of year, but last week’s deep freeze was.

“Even though the temperature was above freezing, the temperature of the earth could have been below freezing,” he said.

When you think about it, it makes a bit of sense. The ground takes a while to freeze in the fall. Why shouldn’t it take some time to warm up, especially after temperatures plunged last week?

The wind didn’t help. Winds blew at 28 mph just before 7 a.m., with gusts to 38 mph. Winds were constant all night and are expected to pick up today. The warmth the air might have given to prevent freezing was literally blown away.

The good news is that snow will continue to stay away this week, but the blustery conditions will continue through Friday. Daytime highs will bounce from the mid-20s Wednesday to the mid-30s on Thursday, only to fall to the mid-teens on Friday.