New flood maps identify risk missed by FEMA after Silver Spring floods

Written in association with FOX 5 DC, read the article here.

MONTGOMERY COUNTY, Md. - After a weekend of severe flash flooding across the DMV, including Montgomery County and Silver Spring, the Metropolitan Washington Council of Governments (COG) says some of the hardest-hit areas weren’t flagged on FEMA’s flood maps.

On Saturday afternoon, a major storm hit the region with little warning. Between 5 p.m. and 7 p.m., Montgomery County’s Emergency Communications Center fielded roughly 100 calls for service, according to past FOX 5 reporting. Firefighters conducted dozens of water rescues during that time, assisting people from vehicles in Potomac, Kensington, Silver Spring and Takoma Park.

Several of the flooded areas in Silver Spring were not marked as flood-prone in FEMA’s current 2020 maps. But the same locations were identified as "at-risk" in COG’s new flood risk assessment, which uses both FEMA data and more detailed projections from the Fathom U.S. Flood Map.

One example is the East-West Highway in Silver Spring, which flooded Saturday. While FEMA’s map does not label that intersection as a flood risk, COG’s updated analysis marks it as "high-risk."

The new flood assessment was developed by COG’s National Capital Region Transportation Planning Board to help planners identify which roads, rail lines, bus stops and bridges are vulnerable to inland and flash flooding, according to a COG statement.

Key findings include:

• Nearly 40% of road miles in the region are already at risk of flooding—almost triple what FEMA maps alone suggested.

• Rail lines, transit stops and other transportation infrastructure show increased exposure in current and future scenarios.

• The recent floods closely matched areas identified as high-risk in the new maps.