Premium ContentMouse over Home then click on Premium Content for information.The Des Moines office of the National Weather Service has recalculated flood stage for streams within its territory because existing stages overstated when flooding would occur.
Jeff Zogg, the Des Moines office senior hydrologist who coordinated the revision, said 44 of 47 gauges required a change in flood stage.
"It is a huge change, something that I've never seen before at my career at weather service," Zogg said of the number of gauges involved and level of changes.
At three gauges, flood stage is increasing by 7 feet; at 12 sites, it's going up by at least 3 feet; and at 18 gauges, it will increase by at least 2 feet.
As a result, Zogg estimates that his office will be issuing half as many flood warnings each year. That means people need to pay attention and not dismiss future warnings, he said.
"These are changing, so when we issue a flood warning, it's going to mean something," he said.
Des Moines serves 51 counties in central Iowa and issues warnings for a number of rivers within that area, including the Raccoon, Iowa, Cedar and Nishnabotna,
The change will go into effect at noon March 14.
• Here's a list of the river gauges that are changing
• Here's an explanation of the changes.
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