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Table 1 A summary how soil burn severity maps were prepared, debris flow hazard was identified, and debris flow risk assessed for the Stanislaus Complex and Rim fires

From: Improvement in quantifying debris flow risk for post-wildfire emergency response

 

1987 Stanislaus Complex Fire

2013 Rim Fire

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