Modeling the Colorado Front Range Flood of 2013 with Coupled WRF and WRF-Hydro System

Abstract:

Abstract. Flash floods are one of the most damaging natural disasters producing large socio-economic losses. Projected impacts of climate change include increases in the magnitude and the frequency of flash floods all around the world. Therefore, it is important to understand the physical processes of flash flooding to enhance our capacity for prediction, prevention, risk management, and recovery. However, understanding these processes is ambitious because of small spatial scale and sudden nature of flash floods, interactions with complex topography and land use, difficulty in defining initial soil moisture conditions, non-linearity of catchment response, and high space-time variability of storm characteristics. Thus, detailed regional case studies are needed, especially with respect to the interactions between the land surface and the atmosphere. One such flash flood event occurred recently in the Front Range of the Rocky Mountains of Colorado during September 9-15, 2013 causing 10 fatalities and $3B cost in damages. An unexpected persistent and moist weather pattern located over the mountains and produced seven-day extreme rainfall fed by moisture input from the Gulf of Mexico. We used a coupled WRF-WRF-Hydro modeling system to simulate this event for better understanding of the physical process and of the sensitivity of the hydrologic response to storm characteristics, initial soil moisture conditions, and watershed characteristics.