Flood Watch Montana | Effective 03/21/2026 07:36

An atmospheric river will bring moderate rain rates to the mountains of western Montana through Saturday afternoon. This will fall on a deep primed snowpack leading to the melt increasing. Flows in rivers and streams may increase and reach bankfull or exceed their banks. * WHAT...Flooding caused by rain and snowmelt continues to be possible. * WHERE...Portions of northwest and west central Montana, including the following counties, in northwest Montana, Sanders. In west central Montana, Mineral. * WHEN...Through Sunday morning. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas. Low-water crossings may be flooded. Rockfall is possible. * ADDITIONAL DETAILS... - The atmospheric river may produce an additional 0.25 to 0.50 inch of precipitation through 3pm Saturday. With conditions already primed, creeks could overflow their banks throughout Saturday. Landslides and rockfalls are possible on windward and leeward sides of the mountains. - https://www.weather.gov/mso/hydrology