Western wildfire risk is increasing in spots following a slow start to the season, the National Interagency Fire Center reported. An exception is Alaska, where fires are already active.
“From what I am hearing from the field, the fine fuels across the Great Basin are now cured and able to support fire activity should it occur,” said Bryan Henry, NIFC Predictive Services acting national fire weather program manager. “The higher elevations are delayed still. The only surprise out there nationally is how wet the Northern Rockies have been and continue to be.”
Much of the Northwest has normal risk, NIFC reported. But areas west of the Cascade Crest in Washington and Oregon, and north along the Canadian border, likely have above-normal risk as heavy fuels remain drier than usual.
Moderate to severe drought remains across much of Washington and Oregon, particularly in western portions. Above-normal temperatures are expected especially west of the Cascades, where below-average summer rainfall is likely. Predicted above-average precipitation for the Rocky Mountains and Great Basin may extend into eastern Oregon and Washington.
In the Northern Rockies, NIFC expects normal significant large fire potential, except across the northern Idaho panhandle and northwestern Montana, where the potential should be above normal through early September in part because of continued moderate drought. Temperatures likely will be above average in much of the region.
Lower elevations in the Great Basin have seen grasses cure in most areas below 5,000 feet except in northeastern Nevada and parts of eastern Idaho and western Wyoming. Boise-based NIFC said fine-fuel loading is well above normal in many lower elevations, though some brush is yet to dry; when that live-fuel moisture drops, large-fire potential will increase quickly in July. The region has above-normal potential for large fires in August and September at lower elevations in western Nevada, and normal potential elsewhere.
Northern California has above-normal July potential for significant large fires, except in the higher-elevation Mendocino National Forest near the central coast. NIFC said factors include dead and down fuels in the northern Sacramento Valley, heavy brush growth and a robust, mostly cured crop of fine fuels. Rainfall was well above average in the 2018-19 season. Risk likely is below normal in the Northern Sierra above 6,000 feet. High-elevation snowpack was above average entering July. Snowmelt likely will conclude by late July, though soil and fuel moisture should linger. Conditions that are warmer and drier than average are expected through October.
Alaska’s season began slowly but by mid-June intensified on continued drying and numerous fire-igniting lightning strikes. NIFC’s July-October National Significant Wildland Fire Potential Outlook said the warm, dry pattern at the end of June “suggested that the state will continue to be active well into July before the season begins to wind down with the arrival of late-summer rains in August.”
Much of the state likely will have above-normal risk of significant fires, with burned acres exceeding the 10-year median, until September.