The National Weather Service released it’s final report on the September flash flood that killed Gorden and Kathy Chapple from Walnut Creek, California, and left the rest of their party stranded.
The slot canyon they were hiking in, Egypt 3, is extremely narrow in places with a person over 200 pounds not able to get through.
According to the National Weather Service less than 1/3 of an inch of rain fell in an hour, in and above the Egypt 3 canyon. The sandstone does not absorb water quickly causing a wall of water over 20 feet tall in the canyon from the 1/3 inch of rain.
For more information of Flash Floods