Updated logistic regression equations for the calculation of post-fire debris-flow likelihood in the western United States

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov/ or call 1-888-ASK-USGS (1-888-275-8747).For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov/.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AbstractWildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can generate dangerous flash floods and debris flows. To reduce public exposure to hazard, the U.S. Geological Survey produces post-fire debris-flow hazard assessments for select fires in the Western United States. We use publicly available geospatial data describing basin morphology, burn severity, soil properties, and rainfall characteristics to estimate the statistical likelihood that debris flows will occur in response to a storm of a given rainfall intensity. Using an empirical database and refined geospatial analysis methods, we defined new equations for the prediction of debris-flow likelihood using logistic regression methods. We showed that the new logistic regression model outperformed previous models used to predict debris-flow likelihood.

Partitioned by process: Measuring post‐fire debris‐flow and rill erosion with Structure from Motion photogrammetry

“…The US Geologic Survey (USGS) post‐fire debris‐flow hazard model provides a tool to quickly assess the probability of debris‐flow occurrence and debris‐flow volume in a basin receiving designed peak 15‐minute precipitation intensities (Staley et al, , ). The USGS post‐fire debris‐flow hazard map produced for the Pioneer Fire shows the study catchment has a debris‐flow probability of 46% under 16 mm/hr peak 15‐minute rainfall intensity and 67% under 20 mm/hr peak 15‐minute intensity (https://landslides.usgs.gov/hazards/postfire_debrisflow/detail.php?objectid=5, accessed October 2016).…”

If It Burns, Will It Flow? and About the Managers Who Would Like to Know: Predicting Post-Fire Debris Flows in the Rangeland Foothills of Boise, Idaho Investigating the Use of Wildfire Science by Decision Makers at the Wildland Urban Interface

“…In contrast to Chapter 3, where we apply USGS post-fire debris flow models to first-order channels where debris flows are interpreted to have occurred within the depositional record , and where differences in modeled debris flow probability and volume could be compared, we apply the models over the drainage basins (third order channels) from which debris flows have been recorded in more recent, written history (Thomas, 1963). The most recent iteration of USGS models (Staley et al, 2016) provide an upper limit of basin size to be used to assess post-fire debris flow hazards, the former models can be used to determine post-fire debris flow hazards over basins as large as 30 km 2 . In the 1959 Lucky Peak Fire study area, the largest drainage basin, Cottonwood Creek, is ~22 km 2 and, therefore, within range of assessment under post-fire debris flow models.…”

“…Cannon and Reneau, 2000, Pierce et al, 2004Staley et al, 2016). High burn severity damages soils, creates ashen material and may induce continuous hydrophobicity across hillslopes, conditions that promote the formation of debris flows.…”

“…Anticipating the location and magnitude of debris flows in recently burned areas has been a subject of study in recent years Cannon et al, 2008;Staley et al, 2016). These studies culminated into the creation of models that predict where debris flows are most likely to occur after fire, and estimate the amount of sediment that the debris flow will deposit , Staley et al, 2016.…”

“…These studies culminated into the creation of models that predict where debris flows are most likely to occur after fire, and estimate the amount of sediment that the debris flow will deposit , Staley et al, 2016. The most recent iterations of these models are commonly used within wildfire perimeters on Forest Service land to target and manage for areas where high debris flow potential intersects resources of interest (e.g.…”