Flash Floods in Zion: How to Spot Them and What to do When Waters Rise

Jun 21, 2019

High water levels in the Virgin River are keeping The Narrows closed later in the season than usual. But despite warnings from park officials, these flood waters are still causing danger to daring visitors who get too close.

The high water of the Virgin River is far from unexpected. This year has seen heavy snowfall and rain throughout Zion. But not all floods are as predictable.

Flash floods are a serious, dangerous threat in Zion National Park and many other parks across the country. Rising fast and unexpectedly, these floods catch hikers by surprise and leave them scrambling for higher ground. In slot canyons and other low-lying areas, this can be a challenge.

No matter the time of year you’re visiting the park, it’s important to be aware of the threat of flash floods. Keep reading to learn what you need to know to keep yourself and your companions safe in the event of a flash flood, as well as what you can do to avoid them entirely.

Why Flash Floods are So Dangerous

Flash floods are incredibly dangerous for a number of reasons. To start, they happen unexpectedly, and rise much faster than most people expect. An area that was previously dry can become inundated with water in mere minutes. But it isn’t just the dry land that can leave hikers feeling a false sense of security; it doesn’t even need to be raining where you are for a flash flood to start. Rain could be occurring miles away from you, but flash floods waters will rush downstream. They can overcome that previously dry trail before you even know that a rainstorm is on its way. Flash floods can also occur hours after a rainstorm has passed.

Another reason why flash floods in Zion and elsewhere in this region are so dangerous is that Southern Utah is full of canyons. Slot canyons are particularly dangerous because they leave hikers with no way to scale the high, flat walls before the flooding becomes dangerous.

Flash floods push a wall of debris ahead of them. Carrying tree trunks, limbs, garbage, and silt, this first wave of the flood can knock down even fully grown, healthy adults. This can make it difficult to get out of the way of the flood waters.

How to Keep Yourself Safe from Flash Floods

While flash floods often catch hikers completely off guard, there are a few things you can do to protect yourself.

Watch the Weather

Check weather forecasts not just in Zion, but in surrounding areas as well. If rain is in the forecast, it’s best to avoid danger spots like slot canyons. Trails at higher elevations are a good choice. You can also opt for several shorter trails that make it easy to get to safety if rain does approach.

Check the Park’s Current Flash Flood Rating

You can always stop by the visitor center to check the weather forecast and talk with rangers about the risk of flash floods on any given day. The national park has a flash flood potential rating system that can help you gauge the threat of flooding that day. The ratings are as follows:

  • Not Expected: If you see this warning, it means that weather forecasts and current park conditions are not conducive to flash floods. However, this doesn’t mean that it’s impossible for a flash flood to occur. Changing weather patterns and sudden pop-up storms can still lead to dangerous conditions. While this rating signals the best days to visit slot canyons and other areas prone to flooding, it is still important to practice caution. Check the weather forecast as often as you can and watch for the early signs of flash floods.
  • Possible: This warning means that while flooding is unlikely in much of the park that day, some slot canyons, dry washes, and small streams could experience flash flooding. If you’re inexperienced at watching for flash floods and new to the trails, it’s best to stick to higher ground when this warning is present.
  • Probable: Weather forecasts and current park conditions mean that flash floods are likely to occur, especially in problem areas like those slot canyons and dry creek or river beds.
  • Expected: The highest flash flood rating possible, when this is posted, its essential to avoid any areas that may be prone to flooding.

The park’s flash flood rating can change throughout the day as weather patterns in the area shift. If you get off of one trail and plan to head to another that is prone to flash flooding, it’s a good idea to check back in to see if the flash flood rating has been upgraded to a more serious level.

Watch for Natural Signs

Flash floods rise in just minutes. But if you know what you’re looking for, you may be able to spot a few early signs. This can give you extra time to seek safe, higher ground.

If it is already raining and you notice puddles forming and growing all around you, this means that the ground has likely become saturated. This means that it can’t soak up any more rainwater. That water has to go somewhere, and that somewhere is downstream.

If you are near an existing stream, watch for an increase in debris or a change in the color of the water. Both can signal that flooding is about to begin.

Finally, the tell-tale sound of rushing water should always be a signal for you to get to higher ground as fast as you can.

What to do if You Do Get Caught in a Flash Flood

Even with lots of planning and awareness of the weather and flash flood rating for that day, things can change rapidly. If you do find yourself caught in a sudden rainstorm or see a flash flood beginning, there are a few things you need to do right away.

If you are in a canyon and it begins to rain, seek higher ground right away. Exit the canyon as quickly as you can. This may mean backtracking on the trail. If you are hiking or canyoneering in a slot canyon, you should seek higher ground even before the rain begins, if possible. Watch for gathering rain clouds or a darkening sky.

If heavy rain begins or you see a flash flood, there is one very important thing to remember; you can’t outrun a flash flood. Many people make the mistake of trying to race downstream ahead of a flood. But that wall of water and debris will catch up fast. Instead, always seek higher ground. Avoid climbing up onto rocks or shelves that may leave you stranded or swimming if the water rises too high.

When flash flood waters rise suddenly, never waste time gathering your gear. Gear can be replaced. But the time it will take you to gather it can be the difference between getting to safety or being caught in the water.

Once you’ve reached higher ground, stay there. Never try to cross flood waters, no matter how shallow. Just 6 inches of water can knock you off your feet and sweep you downstream. It can take many hours for flood waters to recede. If you’ve packed the right supplies, you should have water and snacks to tide you over until it is safe to continue on. Or to keep you safe until rescue crews can reach you.

Protecting Yourself from Flash Floods

Every year, hundreds of hikers in national parks and other recreation areas across the country are caught in flash floods. But while they are sudden and deadly, with careful planning and awareness of the signs to watch for and what to do, you can keep yourself and your companions safe.

Now that you know how to keep yourself safe from flash floods, check out these other safety tips every visitor to Zion should know.