Flash Flood in Southern Utah
On Monday May 11th, 2020, a strong isolated thunderstorm cell developed over the San Rafael Swell in Southern Utah. It produced heavy rain and nickel-sized hail. It fell over Little Wild Horse Canyon, a popular slot canyon for hikers near Goblin Valley State Park, and caused a flash flood that sadly took the lives of two young girls from Northern Utah.
Three graduate students from the Department of Atmospheric Sciences, Tom Gowan, Taylor Gowan, and Kevin Dougherty, were hiking together in Little Wild Horse Canyon at the time. They had checked the forecast prior, which mentioned a roughly 20% chance of rain that afternoon. Once they heard thunder and noticed the dark clouds moving in, they decided it was best to turn around to avoid being caught in a flood. As they hiked down, it started to rain and hail on them and the quickly got to higher ground. Soon after they captured video of the flash flood coming down the canyon, which can be seen below.
After we found a high, sheltered spot, all hell broke lose. Heavy rain turned into the heaviest nickel-sized hail I've ever seen. After several minutes, we noticed a debris flow coming down Bell's Canyon. Video (warning: language): pic.twitter.com/o4hH4DQnjQ— Tom Gowan (@tommgowan) May 12, 2020
My husband, our friend, my puppy and I were caught in this flash flood in Little Wild Horse Canyon today. At the 1st sign of thunder we turned around and got to higher ground. At least 1 life lost. Never underestimate the power of a flash flood. Thankful to be safe. @tommgowanpic.twitter.com/24qyhW0QLT— Taylor Gowan (@tayloragowan) May 12, 2020
Thankfully, Taylor, Tom, and Kevin all made it out safely after waiting for the flow to subside. Tragically, there were two young girls that were caught in this flood and were killed. Tom and Taylor Gowan spoke with Ginna Roe from KUTV about their experience and their interview can be watched here.
KSL also has an article about the flash flood and can be found here.
Additionally, the National Weather Service in Salt Lake City provides Flash Flood Potential Ratings for many locations in Southern Utah, which can be found here. The rating for potential flash floods in the San Rafael Swell on May 11th was listed as Possible. It is important to note that flash floods are possible at any time of the year, not just during monsoon season, and can be caused by a relatively small amount of rainfall. Be sure to check the forecast and these ratings before venturing into areas prone to flash flooding.