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Although wildfires are not an actual weather phenomenon, wildfires are directly related to weather. The wildfire threat across the Inland Northwest normally increases significantly after the middle of June. This threat usually peaks in early July and remains high through August and early September. Wildfires across the Inland Northwest average about 2000 each year.

Wildfire on a mountain side at the 30 Mile Fire near Wintrop of June 2001

Most forest fires in the Inland Northwest are ignited by lightning. Many rangeland and wheatfield fires are also started by lightning. The majority of these lightning caused wildfires occur in the absence or very little rain. When this occurs, the lightning is commonly referred to as "dry lightning". Gusty winds often accompany thunderstorms which produce "dry lightning". These gusty winds accelerate the spread of fires.

Lightning which strikes the ground is usually divided into two categories; negative and positive strikes, depending on the ionic source region of the thunderstorm. The negative strikes are far more common than positive strikes. The positive strikes are more intense than the negative strikes and are more likely to ignite a fire. Advances in lightning detection technology now provide land manages, firefighters and weather forecasters with the ability to identify the general location and charge category of each lightning strike within the continental U.S.

Lightning is often accompanied by winds associated with thunderstorms. Occasionally, the winds are in the form of strong microbursts resulting from rapid cooling of air below the thunderstorm where rain has evaporated. These thunderstorm winds can quickly turn smoldering organic material into a raging fire. Thunderstorm winds tend to be erratic in direction and speed, posing one of the greatest dangers for firefighters.

National Weather Service forecasters help land managers and firefighters by producing fire weather forecasts on a daily basis during the warm season. "Spot" fire weather forecasts are also provided for those who work on prescribed burns or specific wildfires. Forecasters also issue red flag warnings for use by land managers when the combination of dry vegetation and critical weather conditions will result in a high fire danger. Land managers, in turn, typically inform the general public of the fire danger in National Parks, Forests and other public lands.


  1. You should avoid being in areas where you might become trapped by a wildfire.
  2. You should avoid the use of matches or anything else which could ignite a fire.
  3. Make sure that hot parts of motorized equipment, such as mufflers, are not allowed to come in contact with dry grasses or other potentially flammable material.
  4. If you become trapped or cut-off by a fire, seek shelter in areas with little or no fuel such as rock slide areas or lakes.

For more information on wildfires and safety, please check out the NWS Spokane Fire weather web page.