The National Weather Service in Pocatello issued a Red Flag Warning on September 12, alerting residents and land managers to critical fire conditions across parts of southeastern Idaho.
The warning took effect at noon MDT and remained in place until 9:00 PM that evening. It covered Fire Weather Zone 427, which includes the Goose Creek and Raft River Valley areas, portions of the Southern Sawtooth National Forest, and Bureau of Land Management lands south of the Snake River.
Forecasters predicted west winds between 10 and 20 mph with gusts reaching up to 30 mph. Relative humidity levels were expected to drop as low as 13 percent during the warning period.
These conditions meet the criteria for critical fire weather in the region. In southeastern Idaho, officials define critical fire weather as relative humidity at or below 15 percent combined with wind gusts of at least 25 mph in mountainous terrain or 30 mph on the Snake River Plain. Thunderstorm coverage of 25 percent also triggers critical conditions, regardless of rainfall amounts.
Low moisture levels and moderate to strong winds create an environment where wildfires can start easily and spread rapidly. Fire intensity is also likely to increase under these circumstances, making containment more difficult for crews.
The National Weather Service coordinates with area fire management agencies to issue these warnings when conditions pose a significant risk to public safety and property. Residents in the affected zones are advised to avoid activities that could spark fires, such as outdoor burning or equipment use that generates sparks.
NWS Warns of Critical Fire Conditions in Southern Idaho Through Saturday