Post Wildland Fire Response

The western slope of the North Cascades mountains is known for high levels of rainfall, dense evergreen forests, high biodiversity and rugged wilderness. The needle-like leaves of western hemlock and red cedar trees contribute thick layers of organic material, or duff, on the forest floor that absorb moisture. Other trees, like bigleaf maple, hold the soil with deep and expansive root systems. When a wildfire burns through areas of dense vegetation, the fire removes those stabilizing elements, increasing the risk of flooding, mudslides and debris flow. Those potential events in turn pose a threat to visitors and residents within the burned area.

After a wildfire, the burned landscape is assessed to determine if there are post-fire threats from flash floods and debris flows. Critical natural and cultural resources are also assessed for threats from erosion, invasive species, or loss of critical habitat.

The risks present in a post-fire changed landscape will likely last for years and safety of residents, employees and visitors in these areas is of the utmost importance.

 

Burned Area Emergency Response (BAER)

Burned Area Emergency Response (BAER) begins before the fire is completely contained or shortly thereafter. The BAER program brings in a team of specialists to assess the need for effective post-fire stabilization measures to protect human life, property, and critical natural and cultural resources. Teams include experts in hydrology, forestry, cultural resources, botany, wildlife biology, Geographic Information Systems, infrastructure, recreation, and environmental regulatory compliance. They meet with the park management team to identify values at risk from direct fire impacts or conditions following the fire. After spending time in the field making assessments, compiling data, and talking with park specialists, they make recommendations on specific, immediate actions needed.

 

BAER Response: 2023 Sourdough Fire

The Burned Area Emergency Response (BAER) team for the 2023 Sourdough Fire was deployed to evaluate and address threats to human life and safety, many of which come from flooding risks. The BAER team gathered data and information from the field to generate models and create a long-term plan for the site to present to leadership at the park complex and Seattle City Light.

Hydrologists used satellite imagery called Burned Area Reflectance Classification (BARC) to assess soil burn severity. Field work involved comparing these estimates to the actual burned area, by measuring soil charring, root system conditions and the impact on the duff layer. Hydrologists also conducted water repellency tests in the field in both burned and unburned areas.

Back at the office, hydrologists utilized field data to model future runoff and debris flows by simulating different levels of storms and predicting changes in peak flows, runoff volume, erosion and sediment movement. This data helps park and Seattle City Light staff to plan and begin the long-term work of mitigation treatments in at-risk areas, which can take years.