Many of the river forecasts are showing significant increases primarily because the current modeling uses rain projections for the next 72 hours of potential precipitation.
Typical models only account for 24 hours of projected rainfall.
Emergency managers for the three counties, in consultation with the River Forecast Center, remind residents that the current projections should be viewed as one plausible scenario for the upcoming rainfall event.
“What we do know is that over the next 72 hours we are going to see a heavy precipitation event of four to five inches of rain somewhere in the region; what we don’t know for certain is where it will fall,” commented Doug Reed, Director of Emergency Management for Pottawattamie County.
The current 72-hour rainfall predictions estimate a heavy band of rain, upwards of six inches, falling in a northeasterly line from near Columbus, Neb. through Onawa and northwest Iowa.
The heaviest rains in this system falling in this area would have a profound impact on the Missouri River and some of its tributaries.
Emergency managers urge residents to interpret the latest flood prediction in a measured manner based on the high degree of uncertainty of where the heaviest rains will fall.
“We want people to be aware of the possibility of another round of significant flooding, but also aware that it is not certain we will see water at those levels until we get closer to the rain event,” commented Larry Hurst, Emergency Management Director for Mills County.
“Residents should use all available information to take actions they feel necessary, keeping in mind that this forecast is certain to change as we enter the 72-hour window and have better forecast models to work from,” stated Larry Oliver, Harrison County Emergency Management/911 Director.