Fire officials from various Douglas County agencies will be keeping a close eye on the Archie Creek Fire burn area for the coming months, years and potentially decades.
Last Monday, the Federal Emergency Management Agency released its Erosion Threat Assessment/Reduction Team report for several western Oregon wildfires, including the Archie Creek Fire.
The report lays out in vivid detail the threats for debris flows, landslides and property damage as western Oregon moves into its traditionally wettest months of the year.
With the Pacific Ocean in a La Nina weather cycle, heavy precipitation than usual is predicted for the Pacific Northwest throughout the remainder of this winter and into the spring. That threat will have land managers and other agencies keeping their heads on a swivel monitoring potential threats.
“One of the main activities we’re doing through the rest of the winter is storm patrols,” said Cheyne Rossbach, a spokesperson for the Roseburg office of the Bureau of Land Management. “What we’re looking for now is the potential for all that burned material and water coming down.”
During storm patrols, officers will be examining culverts throughout BLM lands impacted by the fire, making sure they are clear of debris buildup, which could cause further issues.
The report shows that nearly 67,000 of the fire’s 131,500-acre footprint was on federal land, primarily managed by the BLM and United States Forest Service.
According to a soil burn severity report, BLM lands took the brunt of the fire’s damage. In the lower Rock Creek area alone, 49,000 acres were burned with 100% efficiency. The Susan Creek drainage, also largely within BLM’s management zone, had 32,000 acres impacted at a 94% burn rate.
Across the fire’s footprint, 43,251 acres burned at what is classified as “high” severity. A high burn severity means that topsoil can be burned as far as 6 inches below the surface for undergrowth, and even deeper for tree root systems, which are expected to continue to smolder throughout the winter and spring.
An additional 57,900 acres burned at a “moderate” classification, which also affects root systems.
More than 100,000 acres of the fire’s 131,542-acre footprint have heavily compromised soils, which means a heightened threat of damage to both public roads and property from potential landslides, rock falls and debris flows.
“In those areas where it burned really hot, it actually creates a hydrophobic surface,” Rossbach said. “The soil just doesn’t absorb water correctly.”
The entire Rock Creek drainage faces a “very high” risk for flows and slides in the event of heavy precipitation, while many parts of the fire in the Susan Creek area and along Highway 138 East face a “high” risk.
That risk assessment is attributed in part to the severity of slopes in the area. Approximately 25% of the fire scar is on slopes ranging from 60-100% in their downgrade.
The Winchester Dam on the North Umpqua River is also at “high” risk for property damage as wood debris and sediment flows present a risk of clogging the dam as well as impacting the dam’s fish ladder.
Recovery for forest life will also take time. The report states that the full recovery of undergrowth and shrubbery could take anywhere from 3 to 5 years in areas that burned at a moderate intensity.
That time frame in the high intensity burn areas is even longer, specifically as it pertains to conifer trees and an overhead canopy The report says that could take 2 to 3 decades to be restored.
Rossbach said that with consistent, smaller rain events throughout the coming months, conditions on the Archie Creek Fire footprint could stay relatively manageable.
“Cross our fingers,” Rossbach said. “If we get that through the winter, that would be great. We don’t want any of those 5 to 10-inch rain events. That’s where things get unstable.”