The National Weather Service in Pocatello issued a Flash Flood Warning for portions of central Idaho on the evening of August 15, alerting residents and travelers to the threat of rapidly rising water across four counties.
The warning took effect at 9:39 p.m. MDT and remained in place until 12:45 a.m. MDT on August 16. Doppler radar detected thunderstorms producing heavy rainfall across East Central Blaine County, West Central Bingham County, South Central Butte County, and Northwestern Power County.
Meteorologists with the National Weather Service warned that rainfall rates could reach 1 to 2 inches within a single hour—a volume capable of triggering flash flooding in vulnerable areas. The agency indicated that flooding was either already underway or expected to begin shortly after the warning was issued.
Small creeks and streams posed the greatest immediate risk, along with urban drainage systems, highway underpasses, and low-lying areas susceptible to water accumulation. Locations including Craters of the Moon and Big Southern Butte fell within the warning zone. Poor drainage areas faced heightened exposure to pooling water and runoff.
The National Weather Service reported no additional rainfall was expected beyond the initial thunderstorm activity, suggesting conditions would stabilize after the warning period ended.
Residents in affected areas were advised to avoid crossing flooded roadways and to stay alert for hazardous conditions on streets and highways. A separate Flash Flood Watch had been issued earlier for the Heise area through Wednesday, indicating the region remained under heightened weather scrutiny throughout the period.
What Comes Next
Residents should monitor National Weather Service updates and exercise caution near creeks, streams, and roadway underpasses until the warning expires. Those in affected counties should avoid unnecessary travel through areas prone to standing water or rapid runoff.