It was one of dozens of wildfires burning in western U. The National Interagency Fire Center in Boise, Idaho, a federal agency that coordinates wildfire-fighting, said 80 large fires were burning on 2, square miles in nine Western states. The square mile fire east of Portland forced hundreds of home evacuations. Embers from the fire drifted in the air across the Columbia River -- sparking blazes in neighboring Washington state.
Study suggests less rainfall in western U. In their paper published in Proceedings of that National Academy of Sciences, the group describes their study of rainfall and fires in the area, and what they found. Wildfires in the western U. Prior research has suggested that the primary reason for the change is an increase in temperatures in the region.
In this new effort, the researchers wanted to know if changes in precipitation were also playing a role. To find out, they studied data collected from weather stations across the region for the years to They compared the data to satellite maps showing where wildfires had occurred and how big they had grown over the same time period.
Before conducting their analysis, the group proposed three main possible factors contributing to the increase and size of fires—that they were due to reduced snowpack, that they were due to higher temperatureor that they were due to lower rainfall.
Their first finding was that a reduction in snowpack was not a factor, either in the increase in fires or how big they grew. Their second finding was that there did seem to be a correlation between higher average temperatures in the area and the changes in wildfire patterns.
Their third finding was that there appeared to be an even more pronounced correlation between declining amounts of summer precipitation and the number and size of wildfires.
More specifically, they found that between 82 and 94 percent of the land area they surveyed experienced less summer rainfall over the time period they studied. They also found that the average forest in the area under study had 4 percent less rainfall per decade, and the worst of them had a 47 percent decline.
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They also found that the average number of days that rainfall exceeded 2. The researchers suggest their data shows declines in rainfall in the western United States are a major factor causing an increase in the number of wildfires and how big they grow.
Decreasing fire season precipitation increased recent western US forest wildfire activity, Proceedings of the National Academy of Sciences However, near-surface air temperature and evaporative demand are strongly influenced by moisture availability and these interactions and their role in regulating fire activity have never been fully explored.
We use path analysis to decompose the relative influence of declining snowpack, rising temperatures, and declining precipitation on observed fire activity increases. After accounting for interactions, the net effect of WRD anomalies on wildfire area burned was more than 2.
These results suggest that precipitation during the fire season exerts the strongest control on burned area either directly through its wetting effects or indirectly through feedbacks to VPD.
If these trends persist, decreases in summer precipitation and the associated summertime aridity increases would lead to more burned area across the western United States with far-reaching ecological and socioeconomic impacts.A new study predicts significant growth in the amount of area burned annually by wildfires across the western U.S.
in the coming decades. Study: Decreasing Number of Rainy Days in Summer Has Increased Western Wildfire August 20, MISSOULA – The number and size of large wildfires has increased dramatically in the western United States during the past three decades.
The National Interagency Fire Center in Boise, Idaho, a federal agency that coordinates wildfire-fighting, said 80 large fires were burning on . Sep 24, · Smoke from Western wildfires is now blanketing much of the United States.
According to the National Interagency Fire Center, a federal project that tracks wildfires and coordinates responses to. Forest fires in the western United States have been increasing in size and possibly severity for several decades.
The increase in fire has prompted multiple investigations into both the causes (3, 4) and consequences of this shift for communities, ecosystems, and climate (5). Days of record heat made the western United States tinder dry in early July Numerous wildfires raced across the dry terrain during the weekend of July 7.
From Washington to Arizona, firefighters were battling fast-moving wildfires that threatened residences, businesses, gas wells, coal mines, communications equipment, and municipal watersheds.