Monsoon season in the Southwest desert brings about a spectacular show of lightning, wind and rain to Moab. Thunder can be heard from miles away as storms roll across the desert drowning the canyons, increasing flow to the river and replenishing water sources. The monsoon season cools down the summer temperatures and decreases the potential of wildfires, but the storms increase danger for popular outdoor recreation.
Monsoon season is caused by a reversal in wind patterns, which funnels moisture from the Pacific Ocean and Gulf of California into the Southwest. The late-afternoon storms generally last from early July to the end of September. Often, the thunderstorms are short and scattered, with heavy precipitation in certain regions while other areas are avoided altogether.
Cloudbursts or prolonged storms can cause powerful flooding to canyons, washes and roads. The water can move debris, people and even cars down ravines. Last year on Sept. 30 a large number of hikers became stuck in Grandstaff Canyon, previously known as Negro Bill Canyon, after the creek flooded and became impassable. By the time four members of Grand County Search and Rescue hiked to the group, the water level had dropped low enough for all parties to walk out of the canyon.
“Flood rescues are generally dangerous because the water is muddy and full of debris,” said Nancy May, member of GSCAR. “It’s safer to sit back, have a seat and wait for the water to recede.”
The Grandstaff Canyon incident echoes another GCSAR call on Sept. 29, 2014 in Kane Creek. Twenty-eight bikers became stranded on the Amasa Back Trail after it flooded. GCSAR set up a rope system with a small pontoon boat to ferry the bikers across, but within four hours of the initial call, the flood water dropped low enough for people to safely walk across.
Flash floods have also been known to take out the campsites of people too close to the washes or creeks such as Courthouse Wash, Onion Creek and Professor Creek. “In Kane Creek, people will have no clue it’s raining upstream in the area’s watershed,” said May. “The view is blocked by 600-foot cliffs.” It’s recommended to set up camp and park cars as far away from the washes and creeks as possible, which are prone to flooding.
In 2016, GCSAR cleared the popular swimming area Millcreek in anticipation of a huge flood due to a heavy rainfall in the La Sal Mountains. “Visitors need to pay attention to the weather while they’re there,” explained May. “Due to its popularity and that it’s in a canyon, a flash flood in Millcreek could be disastrous.”
In Arizona last year, an extremely unexpected flash flood at a popular swimming hole took the lives of nine people on July 16, 2017. The weather at Cold Springs was sunny without a cloud in the sky, but heavy rains just eight miles upstream caused the devastating flooding.
GCSAR wants to avoid such a tragedy happening here, and aims to anticipate and clear Millcreek before a flooding at the same magnitude of Cold Springs.
Canyons should be entered with caution this time of year. “The most dangerous areas for a flash flood are typically the tight slot sections of canyons. A lot of water is being forced into an extremely tight area,” explained Sylvan Christensen, a local canyoneer and professional guide. “It carries debris such as rocks and trees and the flood water would be almost always over your head.” During monsoon season, the chance of a flash flood in a canyon increases significantly. “If there are cumulonimbus clouds around where I am canyoneering, it typically means rain, especially around this time of year,” said Christensen. “My best advice for people who are new to canyoneering, or if they’ve never been in a particular canyon before: If it looks like rain, save it for another day.”
In order to properly plan for a day outside during monsoon season, it’s important to check reliable weather sources, such as Moab Weather Advisory, for warnings. If caught in a storm, “The best place for shelter would be below lightning level but above potential flood area level,” said Julie K. Trevelyan, author of “100 Classic Hikes Utah”. “Stay away from anything that could be a flood run-off channel and always judge the terrain and situation you’re in at the moment and make the best judgment.” It’s recommended to stay away from tall objects and exposed areas, and if on the river or body of water, seek shore immediately. Sandstone, the most common rock in Moab, is weak and porous and prone to rock slides. It’s not recommended to take cover under the rock. “Sandstone just gets incredibly slick during monsoon season [hence its name, ‘slickrock’] when it’s actually raining, so it can make for treacherous footing,” explained Trevelyan. “It also has the potential for breaking off or crumbling due to being waterlogged, so to speak.”
Trevelyan advises, “Best thing to do is keep your head, be very aware of your surroundings, be aware of personal and group safety if in a group, and safely hunker down to wait it out if you can!” And keep in mind another adage used by weather-watchers: “Turn around, don’t drown!”
ByBy Emma Renly