The picture above was taken around 8:30 pm on Monday August 21st, 2006 in the neighborhood of Meteorologist in Charge, Jose Garcia. He noted the water level to be about 2 feet deep along these streets. This forced a number of residents to walk home as their cars were stalled in the rising waters. At least one home in this area had 2 inches of water inside the house with numerous homes around the west side of Amarillo reporting water flowing into basements. Businesses were also affected by the flash flood. The Target department store on Soncy and West Gate Mall Parkway had water rush into the store when one of the back doors broke due to the weight of the water. Baptist Saint Anthonys Hospital on Coulter St. north of Interstate 40 had a muddy water mixture drift into their basement. The Fire and Police Departments were kept busy rescuing stalled motorists through the evening. And of course the most tragic result of the flash flood was the 17 year old male drowning victim.
So what is the difference between a flash flood and a regular flood, and what caused this event in Amarillo? Well, a flash flood is almost self defining. Flash floods aremainly caused by torrential rains, a dam break, or an ice jam break. The key factor is that the water is flowing quickly and occurs within 6 hours of the event causing the flooding. Whereas a regular flood is most commonly associated with large rivers or ocean waters breaching their banks. This may also be caused by torrential rains or a dam failure, but the key would be the slower movement of the water and longer time between the rain and the flood.
Torrential rains from a thunderstorm was the factor that lead to the flash flooding in Amarillo on the 21st. The thunderstorms over Amarillo were generated by two outflow boundaries that merged just north of the city. Below is a series of radar images taken between 7:24 PM and 7:48 PM on Monday shortly after the thunderstorms developed along the merging outflow boundaries. (An outflow boundary is a line of strong winds that are pushed out away from a thunderstorm. They can be a good area for future storm development but often indicate that the source storm will soon dissipate.)
The following images are courtesy of the Amarillo Globe News.
Most of the flash flooding and associated damage took place between the Interstate 40/Interstate 27 interchange and Soncy road, and from 45th Avenue to just north of the Interstate 40.