Seth Binau, a forecaster with the National Weather Service, breaks down the flood warnings and rainfall totals in south-central Minnesota. Biau also describes the makeup of front that brought about torrential rain.
A series of disturbances moving along a stalled frontal boundary dropped extremely heavy rain on much of northern Iowa and southern Minnesota on September 14th and 15th, 2004. More than 10 inches of rain fell in a 36-hour period in Faribault and Freeborn Counties. 6-inch totals were common in the region.
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SPEAKER 1: Most of south central and southeast Minnesota experienced very heavy rains overnight. We currently have flood warnings in effect for about, oh, six counties in south central Minnesota. And I know the National Weather Service office out of La Crosse has some flash flood warnings for southeast Minnesota, where the terrain is a little higher and the flash flood potential is a little greater.
Our warnings are flood warnings, which are for the flatter terrain, where the water just gathers in low-lying areas and small streams might wash out roads and that kind of a thing. But we're just starting to get some rainfall reports coming in. There's a little town east of Albert Lea in the last 36 hours that's had 9.5 inches of rain.
The city of Albert Lea itself has had seven and a quarter since midnight, and the heavy rain is finally moving north out of those areas. But there's other areas of south central Minnesota still getting heavy rain, and our radar estimates that, oh, probably four to 7 inches have fallen in those bottom two tiers of counties in south central Minnesota.
SPEAKER 2: And how long do you expect the rain to be a problem?
SPEAKER 1: Well, the rain's not going to be a problem too much longer down there. It is starting to finally lift north, and that's what the problem was the entire night down there, is there was a stalled frontal boundary basically just in northern Iowa. And there were some really moist air flowing into that frontal zone through much of the night.
And the storms generated along that front and then moved up into southern Minnesota and deposited all the rain. And that stayed put for six to nine hours. And they just got continuous regeneration of thunderstorms over that area.
And now a pretty significant disturbance is moving along that front and is going to lift the front north up over the Twin Cities, and it's going to take that axis of heavy rain and bring it up over the entire state of Minnesota today. So over the real big flood threat areas of south central Minnesota, the heavy rain is going to come to an end early this morning, and it's going to be modified as it comes up over the central portion of the state.
We're not going to see the torrential rains they saw down there because the rain is going to be moving. It's not going to be situated over one point for a very long time. So we'll still get a couple 3 inches of rain across a good portion of central Minnesota, but not like what they saw down there.