The hikers that were rescued said the river swelled within minutes, according to Associated Press.
The stranded hikers were rescued by helicopter and a technique of roping that bound them together with flotation devices to cross the raging water.
On Saturday, the rainfall for the Bear Canyon region was believed by AccuWeather Expert Meteorologist Jim Andrews to be around an inch with temperatures in the middle to upper 50s.
Phoenix broke their 24-hour record rainfall amount with 1.18 inches. Some local rainfall amounts in southern Arizona broke 2 inches. Tucson International Airport observed 0.46 of an inch within a one-hour period on Saturday.
Andrews said that the rainfall came down relatively fast.
“Within an hour, it went from raining not very hard to very hard,” he said.
Runoff from the mountain could have caused the local creek to swell very quickly and without warning, according to Andrews. This could have taken the hikers by surprise.
Andrews also said, the Catalina Mountains are capable of making their own weather, because of “upslope,” which is when winds blow up the mountain.
“The added lift wrings out more water than normal,” he said.
Andrews also offered some “words of desert wisdom.”
“Bodies of water should be off limits. A desert wall of water can come downstream with no warning because of heavy amounts of rainfall in a short period of time,” Andrews said. – AccuWeather.com
- Dozens Of Stranded Arizona Hikers Rescued – NPR (npr.org)
- Dozens of stranded Arizona hikers rescued (seattlepi.com)