Dry spell averting record floods on many rivers

Many rivers are flooding across Minnesota. Some rivers are at or near record levels. Floodwaters are inundating Harriet Island in St. Paul Monday morning.

Floodwaters rising on Harriet Island in St. Paul Monday morning. Image: City of St. Paul

But our dry weather for the past 10 days and a mostly dry forecast for the next 10 days is remarkably well timed.  This fortunate dry spell may be the only reason many rivers will avoid reaching record flood levels this week. If instead, we had storms dropping several inches of spring rain on top of swollen rivers we would likely be watching record, even catastrophic, floods across southern Minnesota.

Dry spell

Minnesota got pounded with a series of 10 winter storms between Jan. 24 and March 14. Those storms dumped more than 4 inches of precipitation in many areas. But Minneapolis St. Paul International Airport has recorded just .01 inch of precipitation since March 14.

90-day precipitation data via Twin Cities NWS/NOAA ThreadEx

Rivers still very high

Even with the dry spell, snowmelt has pushed many rivers to top 10 flood levels. Some have already set a new flood of record this year.

Here’s the hydrograph for Redwood River in Marshall. It has exceeded the previous record by more than 2 feet.

The Minnesota River at Morton is forecast to reach record levels by this weekend.

Crests this week

May rivers will be cresting later this week. If the forecast holds some rivers in southern Minnesota may begin to fall after that. The Minnesota River at Henderson already shows signs of lower levels this week.

Smaller rivers like the Cottonwood River at New Ulm are forecast to fall rapidly this week.

The South Fork of the Crow River in Delano is stabilizing.

The big bubble

This is the big bubble of water that’s been moving down the Minnesota River toward the Twin Cities. Here’s the view I saw from atop the levee in Chaska Saturday.

The Minnesota River is forecast to peak this week in the southern Twin Cities.

The Mississippi River has risen 9 feet since last Thursday in St. Paul. It’s forecast to rise another 3 feet by this weekend. That would mark the seventh-highest flood record for the Mississippi at St. Paul, the highest level in 18 years.

Looking ahead, there’s still major concern in snow-laden areas like the St. Croix and Red rivers. There’s still plenty of snow to melt in those basins. And the longer range forecast models project the prospects for rain on top of those areas increase by around April 4.

Milder air holds

It looks like the Twin Cities will see its first 60-degree temperatures since October on Wednesday. Overall the next 10 days looks milder than average. No big late-season snow in sight as of now.

NOAA via Weather Bell.

Stay tuned.