Agencies assess post-fire hazards across Little Giant burn area

ENTIAT — Residents got a closer look at the ongoing risks left by the Little Giant Fire during an Oct. 14 meeting, where agencies outlined efforts to identify and mitigate post-fire hazards, as well as plan for long-term recovery.

The Little Giant Fire was started by lightning on July 15 in the Chiwawa River drainage, about 30 miles northwest of Leavenworth. Due to high winds the fire experienced significant fire growth of up to 15,000 acres per day, according to the Forest Service. Reaching nearly 173,000 acres, the fire impacted communities across Chelan County, including Lake Wenatchee, Entiat, Chelan and Manson.

Post-fire recovery can take years, partnering agencies emphasized. However, the assessments and actions taken immediately after a fire are critical to mitigating the risks that remain, such as flash floods and debris flows.

In September, the Forest Service started the Burned Area Emergency Response process (BAER), a short-term emergency response that identifies and addresses potential post-fire risks on National Forest lands.

Involving experts such as soil scientists, hydrologists, geologists, the BAER team identifies critical values such as human life and safety, property, and critical natural or cultural resources, evaluates post-fire threats using field assessments and modeling, then recommends time-critical treatments for implementation.

“The key things they're looking at are things like soil erosion and sedimentation, increased flooding, risk of debris flows, hazard trees, and then non-native invasive species coming in post-fire,” said Okanogan-Wenatchee National Forest representative Victoria Wilkins.

One of the main factors the BAER team evaluates is soil burn severity, which allows physical scientists to predict erosion potential, changes to runoff and flood flows, and increased geologic hazards. The more severe a fire’s effects are on the soil, the more likely those soils will erode.

“The really big takeaway the BAER team emphasized is that there is increased risk for debris flow across the entire burn area,” said Wilkins, noting that significant debris flows have already occurred in the Pope Creek area.

The areas of highest concern include the Entiat River drainage, particularly in the southern portions, as well as the Chiwawa River drainage, notably around the Rock Creek area, said Wilkins.

With the report now published, the Forest Service is now moving into implementing its recommended actions, according to Wilkins.

The BAER assessment is limited to Forest Service land. However, the Forest Service shares its data with partnering agencies. For instance, soil burn severity maps were incorporated into Washington state’s Wildfire-associated Landslide Emergency Response Team (WALERT) report.

The report assessed the risk of flash floods and debris flows from the Little Giant wildfire in Chelan County, including field observations, remote mapping of ortho-imagery and lidar, and analysis of U.S. Geological Survey (USGS) debris flow modeling output.

“The first several years before vegetation comes back is when we're most concerned. You might have heard of friends in the Methow who have had floods and debris flows up to five years after the fire,” said Nancy Calhoun of the Washington Geological Survey.

These hazard risk reports are used by the National Weather Service (NWS) to identify at-risk areas and evaluate the level of precipitation that would trigger flash floods or debris flows, according to Senior Service Hydrologist Joel Atwood.

With this information, NWS is able to evaluate incoming storms and issue flash flood warnings. Atwood acknowledged the limitations of weather prediction tools, but that partners were actively working to fill those gaps. One of the strategies has been the utilization of volunteer weather spotters to provide ‘on the spot’ weather reports.

The Oct. 14 meeting offered a behind-the-scenes look at how coordinating partners assess the damage, risk and recovery strategy after the fire. However, it was also an opportunity to help residents understand how to identify post-fire risks for the safety of themselves and their properties.

Chelan County Emergency Management Specialist Rich Magnussen encouraged residents to familiarize themselves with surrounding hazards, stay up to date with weather warnings, and sign up for Everbridge, the county’s emergency alert system.

“These things happen quickly and a lot of times without warning,” said Magnussen.

Though the impacts of the Little Giant Fire may pose threats to life and property in the short-term, it will take years for the area to fully recover from the long-term effects of the fire.

“Recovering from these fires is a long game…It takes a lot of different organizations coming to the table to keep our roads open, keep people safe, and keep people aware,” said Patrick Haggerty, Forestry Program Manager for Cascadia Conservation District.

Cascadia Conservation District offers technical assistance to landowners affected by wildfires and can also offer financial assistance for post-fire recovery efforts like landscape rehabilitation. Okanogan County Long Term Recovery can help those impacted by wildfire with disaster case management, rebuilding assistance and support.

Taylor Caldwell: 509-433-7276 or taylor@ward.media