Estimated probabilities, volumes, and inundation area depths of potential postwildfire debris flows from Carbonate, Slate, Raspberry, and Milton Creeks, near Marble, Gunnison County, Colorado

Estimating post-fire debris-flow hazards prior to wildfire using a statistical analysis of historical distributions of fire severity from remote sensing data

“…Few efforts to estimate potential debris-flow hazards before the occurrence of fire (Stevens et al 2011;Lancaster et al 2014;Tillery et al 2014;Haas et al 2016;Tillery and Haas 2016) have been attempted. Stevens et al (2011) used the presence of vegetation cover as an indicator of fire severity.…”

“…Few efforts to estimate potential debris-flow hazards before the occurrence of fire (Stevens et al 2011;Lancaster et al 2014;Tillery et al 2014;Haas et al 2016;Tillery and Haas 2016) have been attempted. Stevens et al (2011) used the presence of vegetation cover as an indicator of fire severity. Here, the authors assumed a 'worst-case' scenario, where any vegetation cover defined as shrub or forest type, as identified by the National Land Cover Database (Homer et al 2007), was assumed to burn at high or moderate severity.…”

“…Although the approaches of Stevens et al (2011) and Lancaster et al (2014) are conceptually and computationally much simpler than the method of Tillery et al (2014), none of the reviewed methods directly predict dNBR and, therefore, they are of limited applicability when using the current generation of equations for estimating post-fire debris-flow likelihood, magnitude and rainfall intensity-duration thresholds (Table 1). In addition, the methods of Stevens et al (2011), Lancaster et al (2014), Tillery et al (2014), Haas (2016), or Haas et al (2016) were not tested for accuracy against actual post-fire Table 1. Post -fire debris-flow hazard assessment model equations used for predicting likelihood, potential volume and estimated rainfall intensityduration threshold…”

Forecasting the Frequency and Magnitude of Postfire Debris Flows Across Southern California

“…Although more complicated physically based models of debris flow initiation have recently been applied to selected small (<1 km 2 ) drainage basins in southern California (McGuire et al., 2017; Rengers et al., 2019; Tang et al., 2019), such models are not yet practical for hazard assessment because they are computationally expensive and require additional input data that are not generally available across large areas (e.g., high‐resolution digital elevation data, hillslope and channel sediment grain size distributions, and soil infiltration properties). Previous studies have used empirical models of postfire debris flow for prefire planning in combination with various methods to define synthetic distributions of burn severity representing wildfire scenarios (Elliot et al., 2012; Hass et al., 2016; Lancaster et al., 2014; Staley et al., 2018; Stevens et al., 2011; Tillery & Haas, 2016; Youberg, 2008). We adopt a similar approach here to assess a larger area, and we emphasize mapping debris flow hazard in a manner similar to well‐established models for quantifying earthquake hazards in California (Third Uniform California Earthquake Rupture Forecast, UCERF3, Field et al., 2014, 2015a).…”