The National Weather Service issued elevated to critical fire weather condition notices for Oregon and parts of Nevada ahead of the Memorial Day holiday weekend, citing a combination of gusty winds and dangerously low relative humidity that fire meteorologists say are prime conditions for rapid fire growth and spread.

What Critical Fire Weather Means

When the National Weather Service issues a Red Flag Warning or Critical Fire Weather Watch, it indicates that weather conditions in the affected area are ideal for the ignition and rapid spread of wildfires. The key ingredients are low relative humidity — often below 20% — combined with strong, gusty winds that can carry embers well ahead of a fire's main front and push flames toward structures and populated areas before firefighters can establish defensive positions.

The fire weather concerns are expected through Tuesday, with dry conditions dominating the landscape east of the Cascades, where minimum relative humidities are ranging from the single digits to 30%, and afternoon breezes are likely across much of the region.

Lightning Risk on the Horizon

While most of the Western U.S. will remain dry through the holiday weekend, forecasters are watching for the potential of isolated mixed wet-dry thunderstorms across portions of California, the Northern Rockies, and parts of Utah and Colorado. These storms — which can produce lightning and strong outflow winds without delivering enough rainfall to extinguish the fires they start — are a significant source of new ignitions each year in the Pacific Northwest.

Dry lightning events are particularly dangerous because a single storm cell can simultaneously start dozens of new fires across remote terrain, overwhelming initial attack resources and forcing fire managers to triage which incidents pose the greatest threat to life and property.

Eastern Oregon and Washington Most Exposed

The driest conditions are expected to remain concentrated across Eastern Oregon and Washington, where fuels have dried out unusually early due to the record warm winter and minimal snowpack. Rangelands, grasslands, and shrub-steppe ecosystems in these areas are now fully cured and highly receptive to ignition. A single spark from a vehicle, power line, or lightning strike can produce a fire that grows to thousands of acres within hours under these conditions.

What You Can Do

  • Check current Red Flag Warnings at weather.gov/pqr (Portland), weather.gov/boi (Boise), or weather.gov/otx (Spokane)
  • Avoid operating off-road vehicles, ATVs, or equipment that can create sparks in dry vegetation
  • Never park a vehicle on dry grass — catalytic converters can ignite fuels beneath a vehicle
  • Do not burn debris, yard waste, or brush during Red Flag conditions
  • Have an emergency go-bag ready and know your evacuation routes

Fire weather conditions can change rapidly. Residents in fire-prone areas of Eastern Oregon, Eastern Washington, and Idaho should remain vigilant and sign up for local emergency alert notifications.