Decision Support Services and Impacts of the Flash Flood and Debris Flow in Mount Charleston, Nevada, 28 July 2014

A destructive flash flood and debris flow occurred on 28 July 2014 within the town of Mount Charleston, Nevada. Mount Charleston is located in the Spring Mountains approximately 25 miles northwest of Las Vegas and at an elevation of approximately 7,500 feet. An increase in monsoonal moisture over several days combined with an approaching upper-level shortwave trough provided the necessary ingredients to produce thunderstorm development across the region, particularly the higher elevations of the Spring Mountains. Of greater importance was the antecedent ground conditions for portions of Mount Charleston, as heavy rain of two inches fell in less than two hours on the Carpenter 1 wildfire burn scar. The flash flood and debris flow of 28 July 2014 resulted in more than $2 million in damages to Clark County infrastructure and residential property in the Rainbow Canyon Subdivision. This presentation will briefly illustrate key components that contributed to such a high impact event. Impacts to Clark County infrastructure and local residents will be discussed. Finally, National Weather Service Las Vegas decision support services prior to, during, and after the event will be emphasized, including assisting the United States Army Corp of Engineers as they designed a short-term diversion berm and channel to lessen impacts from future rainfall events.