HYDROMETEOROLOGICAL ASPECTS OF THE KANSAS TURNPIKE FLASH FLOOD OF 30-31 AUGUST 2003

摘要

During the period from 2230 UTC to 0130 UTC 30-31 August 2003, a very small portion of the Kansas Turnpike near Emporia, Kansas was inundated with 6- 8 inches of rain. This resulted in extreme flash flooding, six fatalities, and 250,000 worth of property damage. This flash flood was caused by a type of storm called a low-echo centroid (LEC) storm. This study will focus on the synoptic and mesoscale parameters that favor the development of LEC storms as well as hydrological considerations that contribute to extreme flash flooding. An examination of Weather Surveillance Radar - 1988 Doppler (WSR-88D) cross-sectional imagery reveals the LEC nature of the storm with the highest reflectivity contained in the warm portion of the cloud. A moisture analysisshowed that there was a very high influx of moisture into the storm that allowed the storm to develop heavy rainfall characteristics. Additionally, soundings revealed weak instability, weak cloud layer flow, and a deeply saturated sounding which will beshown to be important contributors in the development of highly precipitation efficient storms. The hydrological aspect of this case shows that the natural flow of water was altered and contributed to the extreme nature of this event. The culvert underneath the interstate proved to be inadequate for this volume of water. A meteorological and hydrological comparison of this event with the historic Fort Collins, Colorado flood is made and discussed. These types of storms can become operationally difficult to recognize in a real-time event.