PNW Fire Outlook Warns of Elevated Risk Through December; El Nino Pattern Adds to Concern

Residents and land managers across the Pacific Northwest should prepare for fire season to extend well into the autumn months. The National Interagency Fire Center (NIFC) September-December outlook, released in late August, projects above-normal potential for large wildfires to persist through December across most of the Northwest, far northern California, and central and southern Idaho.

What the Outlook Says

The NIFC outlook is explicit: following the brief relief of early September precipitation systems, outlooks favor above-normal temperatures with no indication of a sustained wet pattern, meaning drying may quickly resume once those systems pass. East of the Cascade Mountains, fuels are described as critically dry and fully cured — meaning they will carry fire readily with any ignition source under moderate or higher wind conditions.

For the Great Basin northwest half, above-normal risk of large fires continues for September due to recent fire activity and what NIFC describes as a pattern of rapidly resuming fire activity after every brief wet spell.

El Nino Adds Long-Term Uncertainty

A strengthening El Nino weather pattern is adding to the long-range concern. The Climate Prediction Center (CPC) expects El Nino to persist through fall and winter, with a greater than 95% chance of a very strong El Nino arriving by November — a pattern historically associated with drier-than-normal conditions across the northern tier of the United States, including the Pacific Northwest. Precipitation is expected to be below normal in the Northwest from September through December, while temperatures lean above normal through the autumn and winter.

East-Wind Events Remain a Key Threat

NIFC specifically flagged the elevated likelihood of at least one moderately strong east-wind event in September. East-wind events — where dry, warm air flows westward out of the interior and down through Cascade passes — are among the most dangerous fire weather scenarios in western Oregon and Washington, capable of driving fire growth at extreme rates into communities west of the Cascades. The agency noted that previous years with similar conditions and El Nino transitions suggest these events are increasingly likely.

Red Flag Conditions Already Observed

Earlier this month, the National Weather Service issued a rare Particularly Dangerous Situation (PDS) Red Flag Warning across portions of eastern Washington and Oregon, including Spokane and Pendleton. The warning was triggered by wind gusts exceeding 40-50 mph, minimum relative humidity values dropping into the teens, and critically dry fuel conditions — the precise combination that drives catastrophic fire starts and rapid spread.

Fuels Remain Critically Dry

Despite early September rainfall bringing temporary humidity recovery to some areas, fire managers stress that the underlying fuel moisture deficit that built through the summer cannot be reversed by a few rainy days. Grasses and fine fuels east of the Cascades are cured and fully receptive to fire spread, and heavy timber fuels in higher elevations remain well below normal moisture levels after a summer of record heat and drought.