Pouring Water on a Frozen, Wet Sponge: Record River Flooding Possible Again Next Spring in Northern Plains, Midwest

Jonathan Erdman
Published: November 6, 2019

Another round of major river flooding is an increasing likelihood next spring in parts of the nation's heartland, according to a new government outlook.

The latest fall flood update released Tuesday by the National Weather Service Central Region said conditions were in place for a "difficult spring flood season" with the potential for "widespread record flooding again" in parts of the Northern Plains and Midwest.

A number of factors have increased confidence in this rather ominous outlook months in advance.

Historically Wet Year-to-Date

This has been one of the wettest years on record in an expansive area of the country from the Great Lakes and Ohio Valley through the central and Northern Plains.

It's been the wettest first 10 months of any year in 125 years of records in Illinois, Michigan, Minnesota, South Dakota and Wisconsin.

It has been among the top three wettest in Indiana, Nebraska, and North Dakota, as well as Tennessee, according to NOAA's October U.S. State of the Climate report released Wednesday.

Statewide precipitation rankings from January-October 2019, compared to other January-October periods dating to 1895. States shaded in darkest green had their wettest Jan-Oct period on record in 2019. Numbers in each state are rankings from driest (1) to wettest (125) Jan-Oct periods since 1895.

Chicago has had its wettest year to date on record through Nov. 5, as have Minneapolis-St. Paul, International Falls and Rochester, Minnesota; Green Bay, Wisconsin; and Muskegon and Sault Ste. Marie, Michigan, according to the Southeast Regional Climate Center.

This anomalously wet weather hasn't simply been in the spring or summer.

September was the wettest on record in North Dakota, and October was among the top 10 wettest in most of the Great Lakes.

Ground Saturated and Soon Frozen

Continued wet weather into the fall is a key point in this spring flood outlook.

Soil moisture is exceptional by early November standards and in the top 1 percent of historical experience for this time of year from Michigan to eastern Montana.

Calculated soil-moisture ranking percentiles for Nov. 5, 2019, are contoured on the map. The 99th percentile indicates soil-moisture levels are in the top 1 percent for the date.

Soaked soil and early fall snow has lead to a difficult fall harvest in some areas.

As of Nov. 3, the corn harvest is only 10 percent complete in North Dakota, 21 percent complete in Wisconsin and 27 percent complete in South Dakota, according to the USDA, far below the averages of 51 to 66 percent.

Since the soil is so saturated, any additional rain or snowmelt can't soak into the ground. Instead, it will runoff into creeks, streams, rivers, lakes and reservoirs.

With much colder air moving in, that waterlogged soil will begin to freeze, only enhancing runoff from any rain or snowmelt until the soil thaws out next spring.

"Imagine putting a soaking wet sponge in the freezer, taking it out, and then trying to pour water on it. The water is going to immediately run off," South Dakota state climatologist Laura Edwards said in the NWS flood outlook, illustrating the status of the state's soil conditions approaching winter and how the soil is expected to respond in spring.

If the soil can't absorb any more water, what about rivers and lakes?

Rivers Still in Flood Since Spring

There's little room for more water in rivers, streams, lakes and reservoirs in the Northern Plains and upper Midwest.

As of Nov. 6, stretches of the Red, James, Missouri, Mississippi and Illinois Rivers remained above flood stage and unusually high for the fall.

Various other smaller tributaries, creeks and streams were running at record high levels for early November, according to the U.S. Geological Survey.

Streamflow status on Nov. 6, 2019, expressed as percentiles. Blue dots show river flow in the top 10 percent for the date. Black dots denote locations with the highest estimated streamflow on record for the date.

Some river gauges on the James and Missouri Rivers had been above flood stage continuously since March, prolonged by a triple whammy of heavy rain and snowmelt, broken levees still in need of repair and dam releases upstream to clear reservoirs for snowmelt next spring.

With colder air moving in, the NWS outlook said, flooded rivers and other low-lying areas may freeze. That could not only encase flooded areas in ice, but would also end the period during which upstream swollen reservoirs could be lowered.

That leads to another potential headache once it warms up.

Ice jam flooding could be more widespread once temperatures rise above freezing, including along stretches of rivers that typically don't experience them.

Last Straw: Wet Winter?

If this wasn't enough, we could see another wet winter ahead.

NOAA's Winter Outlook issued in mid-October called for a chance of a wetter-than-average December to February across the same waterlogged zone from the Great Lakes to Montana.

December 2019 - February 2020 precipitation outlook. Areas in the darker green/brown contours indicate increasing confidence in a wetter/drier than average period.

This wet winter could be in the form of a heavy snowpack heading into spring from a number of winter storms.

Soaking cold rain events could also occur if the jet stream allows above-freezing air to infiltrate the Midwest, at times.

We've almost reached the point at which farmers struggling through soaked and flooded fields might hope for a dry winter and spring just to reset.

"I've been doing this for 47 years and I'm at a loss for words at what Mother Nature has done to us," Randy Richards, a farmer near Hope, North Dakota, told the Associated Press in mid-October.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.