MISSOULA — The Federal Emergency Management Agency has released new draft floodplain maps for Missoula County for the first time in close to five decades.
"Updated topography, new elevations captured by LDAR technology, and an updated hydraulic study," Missoula County Floodplain Administrator Matt Heimel told MTN.
Specifically, areas near Rock Creek, the Clark Fork, and the Bitterroot River saw changes.
"We need updated flood hazard information so everyone understands the risk in our flood-prone areas," Heimel shared.
Flood plains are low-lying areas next to rivers and with development over the years, businesses and homes lie in the floodplain.
An increase in extreme weather events has changed the landscape as well. With that, how water moves across Missoula County has changed too.
“These are areas that can be just prone to flooding in sort of any high water. When we map our floodplains, what we're specifically looking at are those areas that would be inundated in a flood that's large enough to have only 1% chance in any given year. That's our 100-year flood," Heimel said.
The maps depict how much water would cover specific areas if a massive flood occurs.
They also show flood risk; the legend highlights land and properties with the highest hazard.
Since these are preliminary maps, public comment on the accuracy will become available in early 2026.
"A 90-day appeal period where people can submit comments or dispute these. To appeal, they need to essentially prove the map is wrong," Heimel said.
To look at all the new maps along with informational videos from Missoula County, click here.
To get in touch with Heimel and figure out if your property could be affected by a flood, call 406-258-3799.
