The US Forest Service Burned Area Emergency Response (BAER) Team assigned to the Hirz and Delta Fires has developed a Soil Burn Severity (SBS) map.
The preliminary SBS map was derived from satellite data from before and after the fire and was used to estimate how intensely the fire burned. The initial map identified areas with a loss of vegetation cover and potential soil damage.
BAER Team members looked at burned areas on the ground and by air. They verified the preliminary SBS map and determined the characteristics of the watersheds, such as soil and rock types, acreage, and how steep are the slopes.
Using information from ground and aerial surveys, plus knowledge and experience from years of assessing other burned areas, the soil scientists on the BAER Team produced maps showing the level of damage to the soils. The final Soil Burn Severity map classifies the damage as low, moderate, or high.
Eric Nicita, a soil scientist on the BAER Team, explained, “It is important to evaluate the changes in the soils that determine the effects on our creeks and hillslopes after the fire. Fire damaged soils will have low strength, high root mortality, and increased rates of water runoff and erosion. These can affect all resources downslope and downstream.”
Using the SBS map, BAER Team members run models to estimate changes in stream flows and geologic hazards such as debris flows and rock falls. They compare the pre-fire amounts of runoff and erosion to the calculated post-fire volumes.
Using maps and calculated data, BAER Team members will identify the areas likely to be impacted after the fire. Potential treatments to mitigate threats to “Values at Risk”, including human life, structures, roads, trails, streams, cultural resources, and other natural resources, will be evaluated.