Timing of thaws eases risk of spring flooding

Climatologists, at least, can close the books today on a winter that was cooler and snowier than usual, but with a couple of well-timed warm spells.

“It didn't eliminate our spring flooding potential, but pretty much reduced it across the state,” said State Climatologist Harry Hillaker. “This time last year, we still had a lot of snow everywhere.”

Much of that was lost the week of Feb. 13, which saw temperatures in the mid-60s across the state. When Leon, in Decatur County in south-central Iowa, hit 71 on Feb. 17 it was the earliest 70-degree reading in nine years, Hillaker said.

The season's coldest day was Jan. 21, when the temperature hit -30 at Elkader.

Overall, it was 34th-coldest and ninth-snowiest winter on record for the state, Hillaker said. Both measurements continued a recent trend: It was the fourth colder-than-average winter in a row and the fifth consecutive snowy winter, although “last winter was a lot snowier yet than this one and a little bit colder.”

Both Cedar Rapids and Iowa City were cooler and slightly drier than most winters, according to the National Weather Service.

Given a normal spring, Hillaker expects little flooding along most watersheds this spring, with one major and a handful of minor exceptions.

“We're pretty much guaranteed flooding along the Mississippi.” he said. “There's a lot of water stored in that snowpack which has got to move downstream yet” from northern Iowa and southern Minnesota.

That could also mean high water along some smaller Eastern Iowa tributaries such as the Turkey and the Upper Iowa rivers.

“They're small enough basins so that the impact isn't as big an issue,” said Hillaker. “Minor flooding, but hopefully not more than that, unless there's a lot of rain.”

There's no strong indication of that. Hillaker said the weather service's extended outlook “doesn't give enhanced odds in either direction, but if you read between the lines we're a little trending toward cooler than usual, and no real direction on precipitation.”

But we're looking at “a pretty cool and wet period coming up from Friday at least into next week,” Hillaker said.

Climatologists mark seasons by the calendar, with December through February adding up to winter. Traditionalists will wait  to declare spring on the vernal equinox March 20.