What the heck happened in #Norwood yesterday? This is the @fema flood map for the neighborhood around the Hospital. It says “Minimal Flood Risk.” So why did it flood? @NBC10Boston @necn 1/ 
Problem 1: The parking lot off E. Hoyle sits in a bowl. (@googlemaps). With excessive rain, runoff moves from the highest to lowest point. 2/
Problem 2: because of #climatechange were seeing an increase in heavy rain events. Infrastructure wasn’t created to keep up with these rainfall rates. Norwoods historical data only goes back to the 90s, so you can see the data set from Blue Hill. 3/
Since the 1800s the number of 2 inch plus rain falls have jumped from an average of one per year tothree pre-year. 4/
The flow of the Neponset river hit the 10% Annual Exceedece Probability - what does that mean? This event was very significant. 5/
The Neponset reacts quickly to heavy rain. However, the River climbed about 4 feet in minutes. 6/
The flooding near Lewis’ on Cottage Street - Was also the water flowing from a high point to a low point. With 4 to 6 inches of rain in about 90 minutes, infrastructure isn’t able to drain that kind of water. 7/
The problem is, you aren’t required to get flood insurance if you’re not in an area deemed as a flood risk by @fema. This is another example of how you can get damaging flooding outside of a flood zone, because of events exacerbated by climate change. 8/
