ST. LOUIS – Spring flooding is always a major concern for the bi-state area. Snowpack in the upper Midwest, especially upstream of Grafton on the Mississippi River, is a key factor for determining just how big the threat may become.
Historically, deep snowpacks in the north have been linked to major flooding in St. Louis. As that snow melts, large amounts of water surge downstream.
The Great Flood of 1993 is a prime example, where heavy snow in the north combined with soaked ground locally and excessive rainfall, giving rise to catastrophic flooding that lasted through the spring and summer.
This year, however, due to La Niña, the snowpack has been significantly below normal in the upper Midwest, reducing the threat of snowmelt flooding. Despite this, localized extreme rain events during the spring and summer, which have become more frequent in recent years, still pose a risk. Therefore, the St. Louis area must remain prepared for potential flooding from both short-term and long-term events.