Spring Flood Update: Major flooding still likely

Today’s updated flood forecasts from the NWS and the North Central River Forecast Center paints the same basic picture. Major flooding is likely this spring on virtually all rivers in the Upper Midwest including the Red, Minnesota, Mississippi, and St. Croix.

Here are some highlights from today’s updated Spring Food Outlook:

(click to enlarge images)

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 A 10 spring flood 1.jpg

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 A 10 flood cast 2.jpg

I spoke with NWS hydrologist Diane Cooper this week about the updated numbers, and current conditions that go into the updated flood outlook. Here are some highlights.

-In spite of recent snow melt, much of the water equivalent is still trapped in the reduced snow cover as it works its way down toward the soil. There is still a good 3″ to 6″ of “water equivalent” in some much of the snowpack over Minnesota that will melt and run into area watersheds this spring.

-It is very difficult for hydrologists to get exact measurements of just where the water is in the runoff system at this point in the season. South facing slopes have bare ground, but there is still deep snow on north facing slopes and in deep woods. It takes time for melt water to work its way down from snowpack, into fields and farms, into creeks and rivers. Flood gauges will pick up the water increases after the water is already in area rivers.

-The forecast models this spring are showing some remarkably high numbers for certain area rivers. One scenario has floodwaters topping the floodwall in South St. Paul. That could produce results we have not seen in and near St. Paul in years, if not decades.

While the bigger focus is on area rivers, there is also concern this year about flooding on about area creeks such as Minnehaha Creek. Residents and business along area creeks that have not experienced flooding in previous years should take extra precautions this year.

The bottom line is that major (and possibly record) flooding is still likely this year. The weather in the next month will determine just how severe flooding is this spring. If it stays dry and we get a slower melt, flood crests will be lower. If it gets wet and we get a rapid melt with more snow and rain in between, look out.