Flash Flood in Grand County, Utah

Major flooding in Moab and Castle Valley from strong thunderstorm that produced very heavy rain across town, Mill Creek, North Mill Creek, Kane Creek and a drainage above Castle Valley. 1 inch of rain fell in 15 minutes for a rainrate of 4 inches per hour. 2 reported missing in Moab area with an abandoned vehicle discovered in Mill Creek drainage after flash flooding, 1 was found deceased and other assumed fatality but not found.

Very deep tropical moisture associated with the remnants of Tropical Storm Alberto combined with monsoonal moisture was forced through eastern Utah and western Colorado due to a large high pressure ridge over the Central U.S. and a deep low pressure trough over the Great Basin. This deep moisture combined with strong instability and shear to produce widespread severe weather across eastern Utah and western Colorado with thunderstorms producing severe wind gusts, large hail and heavy rain which resulted in flash flooding and debris flows. One particular storm even produced a landspout tornado in southeast Utah. Frequent lightning also resulted in lightning damage in Montrose, Colorado.