Yearly springtime flooding

The combination of springtime snowmelt and rain contributes to flooding in many parts of the U.S. However, it also provides water to those who rely on the melting snow.

Melting snow and rain are both major contributors to Earth’s water cycle, but they can also bring issues to those in low-lying areas and downstream, even in areas where it doesn’t snow at all!

Have you had flood advisories, warnings, or outlooks in your area even though it’s not raining? It could be the snowmelt! For example, many residents in the middle and lower Mississippi and lower Ohio River valleys are all too familiar with this. As spring approaches and temperatures warm, snow melts and that water has to runoff somewhere!

This runoff from the snowmelt empties into the rivers, adding several inches or even feet of water – depending on how much snow melted and how quickly.

The Mississippi and Ohio rivers are not the only ones experiencing a jump in river height. This is also happening in the West and mainly contributes to most of their water supply! Check out the stream flow map from USGS below showing the spike in water flow in feet per second during the springtime on the North Fork American River in California.

Next, we add the rain. The springtime showers and thunderstorms only add to the water levels in low-lying areas, floodplains and rivers that are already swollen by the snowmelt.

The ground can also have a hard time soaking in the water from rain and snowmelt. The ground is in the process of thawing out from the cold, long winter and it can only soak up so much before the rest of the water puddles or runs off.

While this process occurs yearly with the season change from winter to spring, historical events have occurred bringing massive flooding to the areas affected.

According to USGS, January 1996 consisted of a major flooding event in the Northeast and northern Mid-Atlantic, bringing water levels similar to what Hurricane Agnes brought in 1972. The rivers in New York, Pennsylvania and Virginia, including the Potomac River, were swollen after a heavy snowfall quickly melted and was followed by a major rain event. Ice jams also caused problems for those in the Northeast which led to many deaths and home evacuations.

Although this pattern is a yearly occurrence, you can be best prepared for flooding any time.

Have an emergency kit prepared as well as an evacuation route if you live in a flood plain. If you must evacuate or drive during a time of flooding and you approach a water-covered roadway, “Turn Around, Don’t Drown,” as the water is likely deeper than it appears.