Flash floods can be very deadly! Please heed the advice in the video. Flash floods have been responsible for dozens of deaths in the sport of canyoneering. More people have died en masse doing this sport than any other vertical adventure risk sport in the world. In 1999, 21 people were killed by flash flood while canyoneering in Switzerland. In 2008, 7 were killed in New Zealand while descending a canyon. In both cases, downpours preceded the catastrophe. Study the weather! Always be vigilant.
NOAA's weather updates: http://www.nws.noaa.gov/
ATS canyon-based training courses: http://www.alpinets.com/canyoneering.html