Flash flood warnings and danger in Utah national parks and rec areas
Aug 14, 2023, 1:26 PM | Updated: 2:36 pm
Images of flash flooding at Capitol Reef National Park, Photo credit: Capitol Reef National Park
SOUTHERN UTAH — The National Weather Service issued a flash flood warning Monday for west central Kane County and east central Washington County. Flash flooding is also probable in several other areas of southern Utah on both Monday and Tuesday.
The NWS flash flood warning will remain in effect until 5:15 p.m. Areas covered by the warning include Zion National Park and Springdale.
This Flash Flood Warning is for southern portions of @ZionNPS including Pine Creek, Lower Clear Creek, Shelf Canyon, and Spry Canyon. Radar estimates up to 0.5″ of rain has already fallen. If in these areas, find higher ground immediately! #utwx https://t.co/RmA8BPRtcv
— NWS Salt Lake City (@NWSSaltLakeCity) August 14, 2023
Aside from the areas included in the warning, the NWS said flooding on Monday is probable in:
- Glen Canyon National Recreation Area
- Grand Staircase-Escalante National Monument
- Natural Bridges National Monument
- Grand Gulch
- Zion National Park
The NWS said flooding on Tuesday is probable in the above areas again, as well as in:
- Arches National Park
- Canyonlands National Park
- Capitol Reef National Park
Although no thunderstorms show on the radar, Monica Traphagan, senior meteorologist with the National Weather Service in Salt Lake City, said the flash flood risk is due to high levels of water in the atmosphere.
“What we’re seeing across southern Utah is another day where the amount of moisture available in the atmosphere is much higher than usual.”
High atmospheric moisture means a higher likelihood of pop-up thunderstorms that can quickly turn into deadly flash floods.
Causes of flash floods
Flash flooding often stems from two main factors: rain showers in the area and the type of terrain.
Traphagan explained that these sudden floods can happen with “a lot of rain over a short amount of time. But the amount of rain that you need for a flash flood depends a lot on the terrain.”
There are certain areas of terrain that cannot absorb much rainfall, meaning there is a higher risk of flash flooding. For example, areas that have been affected by wildfires have soil that repels water and cannot absorb much moisture.
In several of Utah’s parks, the rocky and dry terrain makes flash floods more common and therefore dangerous to visitors.
“Sure we’re in a desert, but all you need is a quarter-of-an-inch to cause significant issues,” explains Traphagan. “And that’s not difficult to get if you have a thunderstorm over the right area.”
How to avoid flash flooding
The best way to stay safe from a flash flood is to be aware of the weather.
“Thunderstorms can develop very quickly,” explained Traphagan, “and when a flash flood actually happens, you could have very little time to react.”
All of Utah’s national parks should have the flash flood potential rating from the National Weather Service posted, as well as daily weather conditions.
If rain showers or thunderstorms are forecasted near a park you may be planning to visit, Traphagan recommended changing your plans or staying away from the slot canyons and narrows.
“When you’re out recreating and there’s a potential for flash flooding, you want to avoid those slot canyon areas and save those hikes for a day when the weather is going to be dry.”
Staying safe in a flash flood
Aside from being aware of weather conditions, another way to stay safe in a flash flood is to get to higher ground.
“If at all possible you need to find higher ground immediately. Because the water is coming up and you want to be as high as possible and get out of these flood-prone areas,” said Traphagan.
One of the most dangerous places to be in a flash flood is in a slot canyon. This is because water levels can rise rapidly with only slight rainfall, and there are very few places to escape.
Traphagan emphasized that “when you’re out recreating and there’s the potential for flash flooding, you want to avoid those slot canyon areas.”
Flash flood potential ratings and more information can be found here.
