State Climatologist Outlines Long-Term Flooding Risk for Western Iowa Towns
DES MOINES, Iowa –To understand the future risk of flooding in western Iowa, we must first understand what caused it in the first place.
“I hate to use this cliché phrase but it was the perfect storm. We had a record snow-pack across the state, 22.6 inches, which is the highest that we’ve seen in the 132 years of record keeping. When the flooding occurred we had an extended period of above average temperatures and then precipitation on top of that snow pack, so we had anywhere from three to five inches of runoff,” said State Climatologist Justin Glisan.
Because of the soil moisture, the runoff had nowhere to go but the rivers. According to the Omaha Army Corps of Engineers, every Iowa levee from Council Bluffs to the Missouri border failed. Which brings us to the bad news, the snow-pack to the north contains between five and eight inches of water, so the risk of more flooding is absolutely there. On top of that, water has prevented the Army Corps from starting repairs to the levees and towns are defenseless.
“Currently we’ve got teams that are completing some surveillance from the air and starting to assess the conditions of the levee systems,” said Army Corps of Engineers Omaha District Levee Safety Program Manager Lowell Blankers.
But there is good news long-term.
“If you look at the seasonal outlooks that we have we are trending below average temperature wise in the upper Midwest which bodes well for that snow-pack. We should melt that off relatively slowly, not as rapid as we saw in Iowa over the past week, last week,” said Glisan.
With that said, there really isn’t a solid timetable for when the water will recede.
“You look at the amount of water that was put over the levees, it’s effectively holding the water in. The breaches are allowing some of that water to flow back into the river system but yes there was enough water where inundation is a major issue and probably will be for the time to come,” he said.
In the short-term, Glisan says there is an above average risk of precipitation for the area, but they are not predicting an event that would put towns more at risk than they already are.