1 in 100 year floods are taking place with greater frequency

We are dealing with drought this summer, but many years it's far too wet - and the trend is for more late spring and early summer flooding across the Northland. According to the Minnesota DNR, 11 of the state's 21 biggest floods since 1858, what they call "mega-rains", have taken place since 2000. A consistently warmer atmosphere can hold more water vapor, more fuel for thunderstorms, which often stall, producing historic amounts of rain.

June 19-20 Flood Rainfall Amounts. Credit: Duluth National Weather Service

Exhibit A: the mega-flood that hit 11 years ago, dumping 5-10" of rain on soggy ground, creating historic flooding and mudslides across the Northland. The Duluth National Weather Service has a good recap here, but odds are you haven't forgotten. And a warmer (wetter) climate increases the probability of additional mega-rains in the years to come.

Get our free mobile app

100-year floods on the increase. Credit: First Street Foundation

New research released by First Street Foundation says that FEMA has been consistently underestimating the frequency of rare 100-year floods, and far more properties across the US are vulnerable to serious flooding than previously thought. Cutting through the jargon: the statistics used to estimate the odds of flooding can't keep up with a rapidly changing climate. CNN has a good overview of the disconnect.

First Street Foundation scientists conclude: "Precipitation Model (FSF-PM) results reveal that 167.2 million people in the US (over 51% of its population) reside in a county where stormwater system failure is likely to occur today, as those areas are now at least twice as likely to experience severe levels of flooding (associated with the previously thought of 1-in-100-year events) from rainfall each year." Yikes. So what does that mean for the Northland, and my home in particular?

Very small flood risk in downtown Duluth. Credit: First Street Foundation

Duluth has a moderate risk of flooding in the next 30 years. First Street Foundation summarizes the risk: "There are 4,622 properties in Duluth that have greater than a 26% chance of being severely affected by flooding over the next 30 years. This represents 12% of all properties in Duluth."

I took the liberty of plugging in the address of KOOL1017 in downtown Duluth, and I got the results above ("rare event - .2% likely"). You can do the same thing with your property address to get a better sense of flooding risk. Click here to enter your address into the "Risk Factor".

It's free and anonymous, but it may help you sleep a little better at night, especially the next time we get a conga-line of stalled thunderstorms parked over the Northland.