The forecast for the Des Moines River this week was off. By a lot. When the water is rising, two feet is a big difference for those in its path.
If the National Weather Service is going to be wrong, this was at least the way to do it. Two feet lower was much better than underestimating the flood by that amount. And we have some sympathy for forecasters in a situation like this. Not all rainfall impacts conditions the same way. It’s a tremendously complex system.
It wasn’t the only bad miss of the week for the NWS. On Wednesday a number of tornadoes touched down in Iowa. Not only did the Storm Prediction Center fail to identify the possibility, it failed to even issue a watch for the state once the storms began producing tornadoes. Fortunately for Iowa, most were in rural areas and all were relatively weak.
We’re sure forecasters understand the risk in being off by so much, though. There’s a tendency to remember the missed forecasts more than the ones that were right. Over time that can breed complacency, potentially putting people in danger if they fail to respond to what they assume are overhyped warnings.
The missed forecasts this week underscore the fact that weather forecasting remains a combination or art and science. The balance has shifted tremendously toward the latter over the past several decades. Forecasts today are better and more accurate than ever. But Mother Nature can and does surprise people.
Many factors have led to the improvements, but none more so than technology. Better radars allow scientists to peer into storms in ways that would have been science fiction a generation ago. Satellites can spot differences in water vapor, a critical ingredient in storms. Models are better at longer ranges, too. The record-shattering cold this past winter was predicted, at least in broad terms, as much as six weeks before it arrived.
Where we do see a clear need for better work is in the area of flood control. When Sen. Chuck Grassley said Thursday that the U.S. Army Corps of Engineers says flood control is the number one priority, but that “the only time they tell us it’s the number one concern is when it’s flooding,” it sounded familiar.
For years, we heard that line from the corps, but also heard announcements that lake levels were being lowered to protect recreational opportunities. A few years ago, at a meeting here at the Courier, officials with the corps said flood control was one of several factors that come into play when they make decisions. It was, finally, an honest answer.
This year is a bit different from previous floods we’ve watched. We don’t doubt that the corps’ efforts this year have been primarily aimed at controlling flooding. There has been less reluctance in 2019 to close or limit recreational access to use the lakes’ capacity for flood control. It’s a welcome change.
So, when we say there needs to be better work on flood control, we’re not talking about this year’s specific actions. We agree with the speaker on Thursday who said there needs to be a comprehensive approach given the shifting weather patterns that have hit Iowa. Storms have tended to drop more rain, faster, than in the past. It is a trend that warrants updates to the corps’ approach.
There is not, in the end, much that can be done about wet springs like this one. People can only control the responses. This wasn’t a good week for Iowa forecasters. But even failure has its lessons. We remain confident that this week’s misses will be studied, and new lessons may be learned.
The goal remains the same: keep people safe. Despite this week’s record, forecasters do a much better job of that than people often give them credit for.