In its second flood outlook, the National Weather Service in the Quad Cities says the risk has increased to "well above normal." And the risk for tributaries has increased to "slightly above normal."
Hydrologist, Matthew Wilson, says recent precipitation in the north is to blame. "The Upper Mississippi River Basin has received 200-to-400% higher precipitation over the last two weeks than it would normally have in a regular year. And a lot of that fell as heavy snow up there. The Twin Cities also had a torrential downpour one day, and we're seeing that water didn't go into the streams. That actually soaked into the snowpack."
And Wilson says the snowpack up north has not been melting, just the opposite. "They had an inch or so of rain, and so that actually is frozen up in the snowpack right now at the bottom of it. So that's going to come out later. So, the snow water equivalent up there in the snowpack grew pretty aggressively over the past two weeks."
Two weeks ago, the chance of major flooding (18 feet) was 33% at Lock and Dam 15 in the Quad Cities. That's jumped to 69%.
Wilson says the Mississippi at locations from Dubuque to Burlington all have at least a 50% chance of major flooding. And the Wapsipinicon and Rock rivers have increased chances for minor and moderate flooding.
The weather service will release the third flood outlook in two weeks.
