From: Improvement in quantifying debris flow risk for post-wildfire emergency response
1987 Stanislaus Complex Fire | 2013 Rim Fire | |
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Soil burn severity mapping | Observer-based visual identification from helicopter and ground-level promontories; modified by random ground-level soil survey | Computer processing of satellite imagery comparing pre- and post-fire reflectance; boundaries adjusted based on verification by ground-level soil survey |
Identification of debris flow hazard | Use existing debris flow mapping or aerial-photo interpreted mapping of past debris flow occurrence to identify areas of potential debris flows near identified elements-at-risk | Empirical debris flow model combining identified probability of occurrence and likelihood of volume class to show hazard for all drainage basins present in the burned area |
Assessing debris flow risk | Professional judgment using the assumption that debris flows occurrence differed little between burned and unburned areas and resulted from infiltration-triggered failure mobilizing discrete landslide masses | Interpreted based on risk assessment formula using modelled hazard probability and recognizes burned-area debris flows are due to runoff-dominated erosion by surface overland flow |