The National Weather Service in Pocatello has issued a Red Flag Warning for parts of southeastern Idaho, citing dangerous fire weather conditions expected to persist through Thursday evening. As first reported by api.weather.gov, the alert covers Fire Weather Zone 410, which includes the Upper Snake River Valley and Bureau of Land Management lands near Idaho Falls.
The warning was issued on Tuesday, September 9, at 11:39 a.m. MDT, but it becomes effective at noon on Thursday, September 10, and remains in effect until 8 p.m. MDT that same day. Meteorologists warn that the combination of gusty winds and critically low humidity creates an environment where any existing wildfires could spread rapidly, and new ignitions could become difficult to control.
Forecasters predict southwest winds will blow at sustained speeds of 10 to 20 mph, with gusts reaching up to 35 mph. These wind speeds exceed the critical fire weather thresholds established for the region. In southeastern Idaho, conditions are considered critical when relative humidity drops to 15 percent or lower and wind gusts reach at least 25 mph in mountainous areas or 30 mph across the Snake Plain.
Relative humidity levels are expected to plummet as low as 12 percent during the warning period. This dryness, combined with the anticipated wind gusts, meets the criteria for high fire danger. The National Weather Service notes that thunderstorm coverage exceeding 25 percent is another factor in determining critical fire weather, though the primary drivers for this specific warning are the wind and humidity levels.
Residents and land managers in the affected zones should exercise extreme caution with any activities that could produce sparks or flames. The rapid growth potential for fires means that emergency response resources may be stretched thin if multiple incidents occur simultaneously. The warning serves as a heads-up for both the public and fire agencies to prepare for heightened risk.
This alert underscores the ongoing vulnerability of Idaho’s dry landscapes during late summer and early autumn. While the specific geography mentioned in the warning focuses on Zone 410, the broader region remains susceptible to similar conditions when wind patterns shift and moisture levels drop. Local officials often use these warnings to remind communities about fire safety protocols, including proper disposal of smoking materials and caution with outdoor equipment.