The Ottumwa Courier

August 22, 2013

Jekyll-and-Hyde weather not unprecedented

By MATT MILNER
Courier staff writer

---- — OTTUMWA — The drought situation didn't improve in southeast Iowa in the past week, but it didn't get much worse, either. The way things are going this year, that's a step in the right direction.

What the heck happened? The state saw the wettest spring in history this year and southeast Iowa residents needed to consider whether building an ark might be an option. But in June, the rain left and it hasn't come back except for brief visits.

The result is that more than a third of the state has slipped back into moderate drought, while more than 80 percent is abnormally dry, according to the U.S. Drought Monitor. Less than an inch of rain has fallen in Ottumwa this August. Nearly all of that fell on August 6-7.

Has this kind of Jekyll-and-Hyde weather ever happened before?

“It's not a real common thing to have a reversal this time of year,” said State Climatologist Harry Hillaker. “But there have been worse examples.”

Two years in particular come to mind. The spring of 1983 was cool and wet, much like this year. Then summer arrived.

“It was like someone flipped a switch and it went hot and dry,” Hillaker said. “Just the worst timing.”

Planting that year was delayed by the wet spring, so the crops didn't have the strong root systems they usually establish before the summer months arrive. That makes a big difference when dry weather arrives.

It's common sense, really. Topsoil dries out faster than soil a few inches down. It's closer to the hot, dry air. Think of what happens to the edges of brownies in the oven. Contact with the hot metal of the pan dries the edges much more than the rest of the treat.

Officially, there was no drought that year. Yields were still clobbered by the weather.

“We had all kinds of subsoil moisture, but the plants couldn't get to it,” Hillaker explained.

Go back farther into the records, and Hillaker said 1947 had an “even more abrupt transition.” It had a large May snowstorm, much like this year. The rains stopped in July after the wettest June on record. (That record has been broken twice in the years since.) Then it stopped.

August 1947 was, and remains, the hottest August ever in Iowa. The moisture stored from June evaporated quickly.

That has been the saving grace for the summer of 2013. Droughts are frequently accompanied by hot weather. But this year is different. The highest temperature anywhere in Iowa this year is 98 degrees. Comparatively, Hillaker said, that's not all that hot.

The next week probably offers the last, best chance for Iowa to hit the 100 degree mark, with temperatures expected to hit the mid-90s for much of the state. It's possible to have temperatures that high in September, of course, but the chances decrease.

But after more than a year of intense weather shifts, Iowans aren't taking anything for granted.