Watershed Emergency Response Team Report
The WERT found that twenty-two (22) percent of the fire burned at moderate to high soil burn severity, whereas the remaining portion of the fire (78%) burned at low or very low/unburned soil burn severity. Past discussions with Soil Scientists from the United States Forest Service have indicated that soils with higher clay content tend to have less heat penetration than sandier soils (personal communication, Brad Rust and Dave Young, USFS Soil Scientists). This may play a part in the lower soil burn severities observed in the Hennessey Fire, as soils in these areas generally have a relatively high clay content.
Ninety-six (96) Values-at-Risk (VARs) were identified within and downslope/downstream of the fire. Fifty (50) of the VARs are polygons that encompass several individual structures or extended alignments of road. In general, the majority of VARs are likely to be subject to localized flooding and/or localized potential for debris flows.
The ERMiT post-fire surface erosion model predicts mostly a minimal to moderate increase in the rate of surface erosion across the burned area due to the preponderance of low and very low soil burn severity.