US Flood Risk

I am no longer a practicing P&C actuary, but do still follow topics of interest. Today I read the recently issued report from First Street “The 8th National Risk Assessment: The Precipitation Problem”. Could be some useful continuing ed for you if it falls in your practice area. It’s free to download, but they ask you to tell them who you are. Link: Highlights From "The Precipitation Problem".

First Street tries to solve for some of the shortcomings in the Atlas 14 data set on national rainfall to come up with their own precipitation model. That in turn gets fed into their flood model. It highlights some possible huge underestimates in flood return periods in much of the US.

NOAA knows about some of the issues with Atlas 14, and got the funding from Congress to fix them and publish a new Atlas 15. However, Atlas 15 won’t come out until 2027 at the earliest. This report may be a sneak peak into what updated risk estimates may look like when that’s issued.

The infrastructure bill does include a number of flood related projects. This model suggests some of them may be significantly out of step with true flood risk.

Another interesting bit to me is the disconnect between the FEMA special flood hazard area (SFHA) maps and the new FEMA Risk Rating 2.0 rolled out in April 2022. The new risk rating is attempting to charge an actuarially sound premium, but old maps are still being used for mandating insurance and communicating risk to the public. The paper uses an interesting example in Glendale, CA, 91201 ZIP Code. In the old/current FEMA maps, there are zero properties in SFHA in that zip. However, their new average rates in that zip are approaching $6K. You can see this risk in the First Street maps…

If you don’t care about the paper but want to see what the flood model says about risk to your house and neighborhood, you can do that at I think you may only get one complimentary report, so use yours wisely.


First Street is doing a webinar on this study tomorrow. I think it’s free.