Active AlertsUpper Blackfoot and MacDonald Pass

What: Flash flooding caused by excessive rainfall is possible.
Where: Portions of central, north central, and southwest Montana.
When: From Tuesday afternoon through Tuesday evening.
Impacts: Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas and along burn scars.
Additional Details: - Heavy rainfall produced by thunderstorms may lead to flash flooding. Rainfall rates in excessive of 1 inch per hour are possible under heavier thunderstorms. - Some locations that may experience flooding include Great Falls, Bozeman, Helena, Lewistown, Townsend, Fort Benton, West Yellowstone, White Sulphur Springs, Cascade, Big Sandy, Stanford, Lincoln, Belgrade, East Helena, Three Forks, Manhattan, Belt, Geraldine, Denton, Hobson and the Horse Gulch burn scar. - http://www.weather.gov/safety/flood

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.