Spring is coming: Officials provide first St. Croix River flood forecast of season

National Weather Service says there is so far a low chance of high water, but will monitor conditions closely.




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Via the National Weather Service:

St. Croix River flooding, March 27, 2019, when the river was at about 687 feet above sea level, “minor” flood stage. (Greg Seitz/St. Croix 360)

Overall, for the Upper Mississippi River drainage, the risk for flooding is about average on the whole. Owing to dry conditions and limited snowpack, the headwater basins have a risk that is a little less than normal.

The U.S. Drought Monitor bears this out, with abnormally dry conditions across the headwater areas, with normal to even above normal soil moisture from eastern Iowa up into southern Wisconsin.

There is currently little to no probability of minor flooding on the St. Croix at Stillwater this spring, but a lot can change. (NWS image)

Frost depth is less than normal for most of the Upper Mississippi basin, with depth mainly less than a foot. Only the headwater areas are seeing frost more than a foot deep.

Less frost in the ground suggests that once we start getting melt this spring, there will be more that can infiltrate into the soil, and thus less that runs off into waterways.

So, in general, any flooding risk looks to be normal or slightly less than normal for the northern headwater areas. The highest likelihood for flooding risks are along the Mississippi River downstream of Dam 15, as well as Illinois and eastern Iowa tributaries that feed into the Mississippi. The risk for flooding in these areas is slightly above normal.

Your North Central River Forecast Center will continue to closely monitor the situation as we move through February and into March. Updates to our Flood Potential Outlook information will again be provided the last week of February. We all know things will change over the next 4 to 6 weeks, and those changes will be key in just how the flooding situation will evolve this spring.