The National Weather Service held a Spring Flood Outlook webinar on April 4, updating information about expected precipitation and flood possibilities in the MissouriRiver Basin and other drainage areas. While mountain snowpack melt is not expected to be an additional burden, in the eastern Missouri River Basin, the area remains at an “above, to much above normal flood risk.” The region is very wet, with standing water with no place to go, so it will remain vulnerable to future storm systems and rapid temperature increases. A “very active spring flood season” is expected in southern Iowa, southeast Nebraska, Missouri, and eastern Kansas.
According to reports from Wendy Pearson, Deputy Chief for Hydrologic Services, Corey Loveland, North Central River Forecast Center, Kevin Low, Missouri Basin River Forecast Center and Doug Kluck, NOAA NCEI Regional Climate Services Director, moderate to major flooding is already ongoing in Iowa (among other states), and the wet soil conditions and elevated rivers and lakes will keep the region vulnerable to spring and summer flooding from rainfall and thunderstorm events.
Deep frost depths in the north and northwest ensure any runoff or new rainfall flows south quickly, as nothing can soak into the ground. Between April 4 and April 19, there is a chance for two more “significant weather systems” which could bring more rain and/or snow. Additional precipitation from these weather systems would make the Missouri River rise and fall repeatedly throughout April.
With precipitation amounts ranking the highest or near highest in 124 years, the Missouri River reached record stages (provisional) in 40 locations throughout the MissouriRiver Basin.
April through June are traditionally the wettest months of the year. According to the reports, the mid-plains region will likely see continued above normal precipitation in April through July of this year. Luckily, mountain snowpack appears to be near its peak, and currently sits at about average or just above average amounts, and the majority of plains snowpack has now melted. (Mountain accumulation can still be affected by possible spring storms, though.) Unfortunately, the widespread wet conditions and continued above average precipitation over the last several months means it will take quite a while for the area to dry out.
For all of the above reasons, the lower MissouriRiver Basin, including the Missouri River from NebraskaCity to the mouth at St. Louis will likely see episodic moderate level flooding for the next three months.
The National Weather Service advises continuing to monitor future forecasts and outlooks. The next monthly Central U.S. Climate and Drought Outlook webinar will be held on April 18, 2019.