Critical fire weather continues to be a defining feature of the Pacific Northwest fire landscape this week, with Red Flag Warnings issued for portions of both western and eastern Washington as a pattern of thunderstorm activity, low relative humidity, and gusty winds persists.
Western Washington: Dry Lightning Threat
A Red Flag Warning is in effect for portions of western Washington as incoming thunderstorm systems threaten to produce dry lightning — lightning with little to no accompanying rainfall — along with strong southwesterly winds. The National Weather Service warns that the combination of dry fuels, gusty winds, and lightning could spark fast-moving wildfires in areas that do not typically see significant fire activity.
Western Washington is particularly vulnerable during these events because communities there are less accustomed to wildfire risk, evacuation planning may be less established, and fuels in drier microclimates — including rain shadows east of the Olympics and Cascades foothills — can be critically dry by mid-July.
Eastern Washington: Okanogan Highlands and Kettle Mountains
Earlier this week, the National Weather Service issued a Red Flag Warning for the Okanogan Highlands and Kettle Mountains (Zone 699), the Colville Reservation (Zone 702), and the Okanogan Valley (Zone 703), citing low relative humidity, gusty winds, and dry lightning potential. The Kaiser Canyon Fire — now exceeding 60,000 acres — ignited during this period of elevated fire weather.
Fuel Conditions: The Underlying Driver
The NIFC reports that Pacific Northwest fuels are currently cured to levels typically associated with mid-August. Fine dead fuels — grasses, shrubs, and small-diameter woody material — have lost enough moisture to ignite easily and carry fire at high rates of spread. This early cure is the product of a drier-than-average spring and persistent heat through early July.
1-hour fuel moisture readings in parts of eastern Oregon and eastern Washington have dropped below 3 percent during afternoon hours — well into the "critically dry" range where fire spreads aggressively and is difficult to control.
The Role of Convective Thunderstorms
The Pacific Northwest is currently in what fire weather forecasters call a "lightning bust" pattern — a period of repeated convective thunderstorm activity that generates hundreds to thousands of lightning strikes with minimal rainfall. This pattern, driven by an unstable air mass and upper-level disturbances moving through the region, is responsible for the majority of new fire starts over the past two weeks.
The Northwest Interagency Coordination Center (NWCC) has been tracking lightning strike density in real time and pre-positioning initial attack resources ahead of forecasted storm cells. However, with dozens of simultaneous starts possible during a single overnight storm event, initial attack resources can quickly become overwhelmed.
Looking Ahead
The extended outlook through late July offers little improvement. Above-normal temperatures and below-normal precipitation are forecast across the entire Pacific Northwest. Fire weather forecasters are watching an additional weather system expected to move through the region mid-week, which could bring another round of dry lightning. Residents across Oregon, Washington, and Idaho should treat current fire weather conditions as a sustained elevated threat — not an isolated event.