If you’re planning on taking a trip to Zion National Park or one of Utah's canyons such as Buckskin Gulch, one of the biggest dangers you’ll face is a flash flood. On Monday Sept. 14, 2015, seven hikers in the Keyhole Canyon died after getting caught in a late-afternoon flood. Although there are flash-flood warnings from the National Weather Service on the Zion National Park website (www.nps.gov/zion/planyourvisit/weather-and-climate.htm), it can never be known for sure whether or not flash floods will occur.
Flash Flood 101
“Essentially, around here the cliffs and landscape act more like concrete and so when it rains, everything pours off pretty quickly,” says Alyssa Baltrus, Zion National Park Chief of Interpretation and Visitor Services. She’s been a park ranger for more than 20 years and at more than 10 different parks. “It doesn’t have to rain directly over you. It just has to rain anywhere at a higher elevation than you.”
Flash floods are the most dangerous type of flood because they have the destructive power of a normal flood combined with raging water, in addition to being unpredictable. Each year in the U.S., floods kill more people than hurricanes, tornadoes or lightning. Flash floods can occur from storms that are miles away that increase water levels within minutes or seconds. They can bring walls of water rushing through canyons up to 12 feet high, so it’s best to be prepared prior to starting your trip
Planning for Your Zion Trip
There are certain times of the year when flash floods are more likely to occur. Monsoon season, which runs from mid-July to mid-September, is when flash floods have the highest probability of occurring. During the fall, when there can be tropical storm weather from the Pacific Coast, flash floods also can be likely says Baltrus. During this time of year, entering any slot canyon from the bottom of a wash can be potentially dangerous, even a dry wash.
Before heading out on your hike, check Zion National Park’s website for flash-flood forecasts and look into the general weather prior to embarking on your trip. Flash flood potentials for the day of and the following day are posted at all the visitor centers and contact stations as well. If you have doubts about the weather, it’s best not to venture into the canyons. You can also speak with rangers to gain a better understanding of the weather and hazards of the area.
Signs of Potential Flash Floods
While on your hike, there are signs to watch for that can help you identify the start of a flash flood.
- Changes in water levels or the speed of the water.
- Changes in the color of the water from clear to murky or muddy.
- If you start to see more debris in the water.
- If you start to hear rushing water or loud noises.
- If it starts to rain near you or you see a build up of storm clouds.
If you notice any of these signs, it’s best to get out of the bottom of the canyon. Seeking higher ground immediately. Even just a couple of feet can help save your life.
Luckily, there haven’t been any casualties from flash floods in the 2016 season, but there have been quite a few in the past.
“It’s a lot of monitoring,” says Alyssa in regards to dealing with potential flash floods. “We close down the canyon if we’re under a flash flood warning. Then we monitor and watch.”
The rangers are aware of hikers that have permits and might be in the canyon; if they haven’t returned, rangers will go and search for them. However, during the flash floods the rangers don’t put themselves in danger.