Our experiment highlights the benefits and limitations of this approach, and provides an initial step toward further developing situational awareness and impact-based decision-support tools for forecasting PFDF hazards. We visualize the model output in several ways to demonstrate most likely and most extreme outcomes and to characterize uncertainty. The observed 15-min maximum rainfall intensities are captured within the ensemble spread, though in highest ∼10% of members. We present a concept for probabilistic tools that evaluate PFDF hazards by coupling a high-resolution (1-km), large (100-member) ensemble 24-h precipitation forecast at 5-min resolution with PFDF likelihood and volume models. Forecasters and emergency managers need additional tools that increase their confidence regarding occurrence of short-duration, high-intensity rainfall as well as tools that tie rainfall forecasts to potential PFDF outcomes. The approach of messaging on potential hazards given favorable conditions is generally effective in avoiding unanticipated PFDF impacts, but may lead to “messaging fatigue” if favorable triggering conditions are forecast numerous times, yet no PFDF occurs (i.e., false alarm). A debris flow doesnt need a long rain or a saturated slope. However, at these lead times, considerable uncertainty exists regarding rainfall intensity and whether the high-intensity rainfall will intersect the burn area. What causes a debris flow Debris flows occur most commonly during intense rain after wildfires. (a) When boulders moved at the same flow velocity as that of the mudflow or the flow surface appeared smooth, the flow was interpreted as a laminar surge. ![]() Existing weather forecast products allow forecasters to identify favorable atmospheric conditions for rainfall intensities that may exceed established thresholds at lead times needed for decision-making (e.g., ≥24 h). Debris flow observation results: (a) debris flow composition ratio, (b) flow velocity, and (c) elevation of the surface of the debris flow or deposited material. ![]() Following a wildfire, rainfall thresholds are developed that, if exceeded, indicate high likelihood of a PFDF. They are triggered by short-duration, high-intensity rainfall. “Throughout the course of the construction, the work area will be closed to the public for the safety of both the public and workers.Post-wildfire debris flows (PFDF) threaten life and property in western North America. 'Intense rain means a burst of rain at a fast rate, about half an inch in an hour. It can start on a dry slope after only a few minutes of intense rain. A debris flow doesn't need a long rain or a saturated slope. Later in 2024, we will construct the concrete debris barrier and outlet structure,” explains RDEK Manager of Engineering Brian Funke. What causes a debris flow Debris flows occur most commonly during intense rain after wildfires. Herein, we use the term debris flow as defined by Hungr et al. “The first priorities for construction will be focused on the access road, water main relocation, creek diversion, basin excavation and starting the outlet structure. Debris flows represent an important natural hazard and the correct understanding of the associated mechanisms is essential for adequate mitigation of their impacts on both infrastructure and society (Jakob and Hungr, 2005). RDEK officials said the project includes a barrier and outlet structure to capture debris, a creek diversion and basin for debris storage reinforcement and relocation of some of the water lines and construction of an access road. This is the 2nd edition of one of the most comprehensive accounts of debris flow, describing both theoretical and applied aspects. “The project site is located on property owned by the Fairmont Hot Springs Resort and the RDEK is grateful for their ongoing support and contribution to the project.” I am excited to be at the point where construction is officially getting underway,” said RDEK Electoral Area F Director Susan Clovechok. “There has been extensive work by staff, with support from our Board, during unprecedented construction cost fluctuations to secure funding and refine the design and project scope to allow the project to move forward. It is a typical debris flowoutburst floodlandslide chain with intense cascading effects. ![]() Work is now underway on the Cold Spring Creek Debris Flow Mitigation project in Fairmont Hot Springs. Debris-flow deposition forced the river course to move to the left bank, and then the rapid flow strongly eroded the foot of the old Aniangzhai (ANZ) landslide, leading to the reactivation of the 6.2 × 10 6 m 3 landslide.
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