Floodplain Information

Chances of Flooding

If you live in a floodplain, you have a 26% chance of being flooded during a 30-year mortgage period. Compare this to your 4% chance of fire during that same period. You don't need to live near water to be flooded. Just an inch of water can cause costly damage to your property.

Floodwaters can cover much of the county and are very dangerous. Even though floods may appear to move slowly (three feet per second), a flood two feet deep can knock a man off his feet and float a car. Your property may be high enough that it has not flooded in the past. However, it can still be at risk for future flooding. Call the County Floodplain Administrator at 406-454-6905 to determine if your property is in a floodplain.


Historical Flood Events in Cascade County's History

Flood events have occurred throughout Cascade County's history periodically, according to the Federal Emergency Management Agency (FEMA) Flood Insurance Study, flood events occurred in:


Cascade County is commonly swept by high westerly winds called "chinooks". These winds can create rapid snowmelt events in March or April and can cause flooding while the ground is still frozen. Flood events have also occurred due to heavy snowmelt in May and June, or high-intensity rainstorms later in the summer. Among the areas regulated through the Cascade County Floodplain Regulations are the Sun River, Missouri River Basins, Belt Creek, and Sand Coulee Creek.

Outreach Completed by Cascade County's Floodplain Administrator

Cascade County makes a concerted effort to reach out to County residents concerning the threat posed by flooding. The Floodplain Administrator's office keeps all of FEMAs Flood Insurance Rate Maps, recorded Elevation Certificates and Letters of Map Amendments, and numerous other Flood-related information. The County specifically reaches out to realtors, insurance agents, and lenders with newspaper ads. The most recent newspaper ad was in the Great Falls Tribune on March 27, 2022.


What Can You Do to Help Prevent Flooding?

Several of the County's efforts depend on your cooperation and assistance. Here is how you can help:

  • Do not dump or throw anything into the ditches or rivers. Even grass clippings and branches can accumulate and plug channels or culverts. A plugged channel cannot carry water and when it rains the water has to go somewhere. Every piece of trash contributes to flooding.
  • If your property is next to a ditch or stream, please do your part and keep the banks clear of brush and debris.
  • Always check with the County Floodplain Administrator, the Cascade County Conservation District, or the Army Corps of Engineers before you build on, alter, regrade, or fill on your property. A permit is needed to ensure that projects do not adversely affect other properties down or upstream.
  • If you see a building or filling in the County, please call the County Floodplain Administrator at 406-454-6905.
  • Check out information for: