Fiery Furnace at Arches National Park. (Devon Dewey.)
SALT LAKE CITY — An increased flash flood risk in southern Utah prompted the National Weather Service to warn people to be careful if they’re visiting the area’s national parks.
Glen Merrill, a hydrologist for the National Weather Service in Salt Lake, said the potential for flash floods will increase throughout the week.
“So right now we’re getting the initial surge of monsoonal moisture working into primarily central and southern Utah,” said Merrill.
The Weather Service said the areas that are more likely to see flash flooding are slot canyons, normally dry areas and places where wildfires have burned away vegetation.
“If you get heavy rain in a steeper basin or a slot canyon area, you’re dealing with slick rock, no vegetation, all of the rainfall just runs off of the landscape,” Merrill said, adding “All of that rain, like a funnel, starts higher in the basin and funnels down through these narrow corridors where it all pools together and creates a flash flood.”
Merrill said heavy rain is likely to turn into a flash flood in slot canyons, even if it isn’t raining exactly where you are.
“You can be in terrain — like in a slot canyon — where it’s not even raining overhead, but it might be raining 10 miles away and all of that rainfall eventually comes down through the channel to where you’re at.”
By Thursday, the National Weather Service is predicting flash floods will be probable in Arches, Canyonlands, Capitol Reef and Zion National Park.
Merrill said if you’re going to a national park this week, check the weather before you leave and prepare for fast-moving water. He also recommended checking with park rangers when you get there and asking about the weather.
“Keep an eye to the sky when you go out and prior, gather as much weather information as you can,” Merrill said.
The Weather Service also recommended visitors to national parks create a plan for what to do if caught in a flash flood.