In early September 2020, severe winds, high heat, and prolonged drought conditions led to the explosive growth of wildfires along the western slopes of the Cascades Mountains in the Pacific Northwest.
In early September 2020, severe winds, high heat, and prolonged drought conditions led to the explosive growth of wildfires along the western slopes of the Cascades Mountains in the Pacific Northwest. The fires engulfed enormous tracts of forestland, destroyed communities, took dozen of lives, and cost hundreds of millions to fight.
In a first-of-its-kind study examining burn patterns from the 2020 Labor Day fires, researchers at Portland State University studied the influence of weather, topography, vegetation and other factors on burn severity in areas where the fires killed more than 75% of the trees. Their research confirms that extreme winds over the Labor Day holiday were the primary driver of the destructive force of the fires yet demonstrates how forest vegetation structure (e.g., canopy height, the age of trees, etc.) and topography played a significant role in burn severity patterns.
The paper, "Extreme Winds Alter Influence of Fuels and Topography on Megafire Burn Severity in Seasonal Temperate Rainforests under Record Fuel Aridity," was recently published in the journal Fire.
According to the study's co-author, Andrés Holz, associate professor of geography at Portland State, the wet temperate forests of the Cascade Mountains in the Pacific Northwest have a history of experiencing megafires of the scale of those that burned in 2020, but none had occurred since the early twentieth century. Because the scope and scale of the burns were unprecedented in modern times, they provided the research team a unique opportunity to gain a better understanding of the factors that influence the high severity of burns in these rainforests, including those on the western slopes of the Cascades. That understanding can inform planning for future land-use management in forestlands and the social and ecological impacts of extreme fire events in the context of a warming planet.
Read more at: Portland State University
Satellite image of the Riverside fire in Oregon, 2020. (Photo Credit: Cody Evers)
