Study confirms 2020 extreme wildfires in western Oregon were not unprecedented
By the United States Forest Service
When the 2020 Labor Day fires burned more than 300,000 acres in the space of two weeks in parts of western Oregon and Washington, they devastated communities and highlighted the threat west side fires. A new study by the USDA Forest Service’s Pacific Northwest Research Station examines the context surrounding the fires and offers insight into the historical role of large, high-intensity fires – and the future of wildfires – in the West waterfalls.
“Without a doubt, the Labor Day fires of 2020 were a significant fire on many levels, and a wake-up call for the region,” said Matthew Reilly, forest researcher and lead author of the study, who is published in the journal Ecosphere. “The goal of our study was to help understand how this event compared to past fires on the West Side so that we can help inform adaptation strategies to prevent or mitigate similar events in the future.”
Drawing on a review of the literature, extensive historical data, and new analysis, Reilly and her co-authors explored five questions surrounding the Labor Day fires of 2020: How the 2020 fires compared to historic fires in the region, the role of weather and climate, the effects of forest management and forest structure before the fires on the severity of the fires, the impacts of these fires on the landscapes of the west side and what can be done to accommodate similar fires in the future. Ultimately, they found that the 2020 fires were remarkably consistent with historic fires on the west side, both in terms of timing and size and cause of their rapid spread – dry conditions combined with strong gusty winds. is.
“Our results suggest that these severe fires are normal for west side landscapes when you look at historical fire regimes at longer timescales,” Reilly said. In fact, researchers have identified similar historic fires in the early 20th century under similar weather conditions — some even burning right around Labor Day — in some of the same places that burned in 2020.
Due to the abundant and productive forests characteristic of the west side and the driving role of extreme winds, conventional fire management tools used in dry forests, such as prescribed burning and fuel management, are likely to be less effective in southern forests. west side than they are on the east side. This is especially the case, according to their study, when fire weather conditions are as extreme as those seen during the 2020 fires.
“Our study indicates that we need very different approaches and coping strategies in west-side forests compared to those we use in dry forests,” Reilly said.
The study was conducted as part of Pacific Northwest Research Station’s ongoing West Side Fire Research Initiative, which was launched in 2019 to develop scientific tools to help resource managers respond to the risk of fire in the forests on the west side. The study co-authors are from the Washington State Department of Natural Resources, the University of Washington, Oregon State University, and the Service’s Pacific Northwest Region. USDA forester.
- The 2020 Labor Day fires were much larger and more severe than others in recent record, but they were remarkably consistent with many historic fires. Strong easterly winds and dry conditions are the common denominators of historic large fires in the past and the fires of 2020.
- Forest management and fuel treatments are unlikely to influence fire severity in the most extreme wind-driven fires, such as the Labor Day fires of 2020. Forest structure before the fires, largely the result of past forest management activities, had little effect on fire severity when easterly winds were strong during the 2020 fires.
- Combustible treatment around dwellings and infrastructure can still be beneficial in low and moderate fire weather conditions.
- Strategies to adapt to similar fires in the future in communities on the west side may instead focus on fire prevention, fire suppression and community preparedness.
Matthew J. Reilly et al, Cascadia Burning: The historic, but not historically unprecedented, wildfires of 2020 in the Pacific Northwest, USA, Ecosphere (2022). DOI: 10.1002/ecs2.4070
Wildfire Today, September 2020 articles tagged Oregon or Washington.