Omaha-metro's 2020 flood outlook according to Chief Meteorologist Rusty Lord
have led to some worry about whether we are headed towards a
repeat of 2019.
came to be — and why a repeat is not likely, especially along the Platte and Elkhorn rivers.
Record February snowfall and a Top 10 coldest February were the main drivers that set up the flooding event that we experienced in mid-March. Omaha recorded 27 inches of snow in February and high amounts similar to that were common across much of the area.
It was also a Top 10 coldest February on record, leading to frost depth well over a foot heading into March. This set the stage for large amounts of water content available to melt and nothing for it to soak into, and runoff was likely to be a big problem with a quick melt.
Unfortunately, a quick melt was just what happened. Highs in the 40s on March 12 started the melting process and it really sped up over the next 24-48 hours. Highs in the 50s and 60s on March 13 combined with 1-3 inches of rain added even more moisture and caused the snow to melt even faster. This is what led to incredibly fast rises on the Platte and Elkhorn rivers that caused so much damage early on in this flood event.
Thankfully, this year we lack the snow cover that would cause us to be concerned about an event like that along the Platte and Elkhorn rivers.
There is concern about thicker snow cover farther upstream along the Missouri River into South Dakota, though. The James & Big Sioux River in South Dakota will be watched very closely in regards to flooding along the Missouri River.
In eastern South Dakota, 10 to 15 inches of snow cover will flow into those two rivers as the spring thaw progresses.
Both rivers also empty into the Missouri downstream of Gavin’s Point Dam, so the dam will offer no control of those waters if a rapid melt occurs. Therefore, the potential for the biggest flooding issues in our area this spring resides along the Missouri River.
The rate of snow-melt in South Dakota and the path of spring rains will be two huge factors that determine just how big of an issue the flooding will be along the Missouri River this year.