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Predicting the probability and volume of postwildfire debris flows in the intermountain western United States

Geological Society of America Bulletin

By:
, , , , , and
DOI: 10.1130/B26459.1

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Abstract

Empirical models to estimate the probability of occurrence and volume of postwildfire debris flows can be quickly implemented in a geographic information system (GIS) to generate debris-flow hazard maps either before or immediately following wildfires. Models that can be used to calculate the probability of debris-flow production from individual drainage basins in response to a given storm were developed using logistic regression analyses of a database from 388 basins located in 15 burned areas located throughout the U.S. Intermountain West. The models describe debris-flow probability as a function of readily obtained measures of areal burned extent, soil properties, basin morphology, and rainfall from short-duration and low-recurrence-interval convective rainstorms. A model for estimating the volume of material that may issue from a basin mouth in response to a given storm was developed using multiple linear regression analysis of a database from 56 basins burned by eight fires. This model describes debris-flow volume as a function of the basin gradient, aerial burned extent, and storm rainfall. Applications of a probability model and the volume model for hazard assessments are illustrated using information from the 2003 Hot Creek fire in central Idaho. The predictive strength of the approach in this setting is evaluated using information on the response of this fire to a localized thunderstorm in August 2003. The mapping approach presented here identifies those basins that are most prone to the largest debris-flow events and thus provides information necessary to prioritize areas for postfire erosion mitigation, warnings, and prefire management efforts throughout the Intermountain West.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Predicting the probability and volume of postwildfire debris flows in the intermountain western United States
Series title:
Geological Society of America Bulletin
DOI:
10.1130/B26459.1
Volume
122
Issue:
1-2
Year Published:
2010
Language:
English
Publisher:
GSA
Contributing office(s):
Landslide Hazards Program
Description:
18 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geological Society of America Bulletin
First page:
127
Last page:
144
Country:
United States