Latest / Wildlands Podcast — National Parks, Public Lands & Survival / #008 - Field Skills: Flash Floods | Reading Water, Weather & Slot Canyons

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#008 - Field Skills: Flash Floods | Reading Water, Weather & Slot Canyons · Wildlands Podcast — National Parks, Public Lands & Survival

• 0:10
  Picture where you are standing. You are two miles
• 0:13
  into the narrows, somewhere around Wall Street.
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  The walls rise a thousand feet above you on both
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  sides, so close in places you could almost touch
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  both at once. The water is cold and clear around
• 0:25
  your ankles. The light coming down that narrow
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  slot is unlike anything you have seen before,
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  soft, diffuse, bouncing off sandstone in shades
• 0:33
  of orange and gold. You are having one of the
• 0:38
  best days you have had outdoors in your life.
• 0:42
  And seven miles upstream, on a plateau you cannot
• 0:45
  see and would not think to look at, a thunderstorm
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  just dropped an inch and a half of rain in 40
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  minutes onto ground that is baked clay. That
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  water has nowhere to go except down. It is in
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  a gully now, then a wash, then the Virgin River.
• 1:00
  And it is moving toward you. You have maybe 15
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  minutes. This is Wildlands. I'm Sean. Know the
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  land before you reach it. Field skills flash
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  floods. Flash floods kill more people in the
• 1:18
  United States in an average year than lightning,
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  tornadoes, or hurricanes, not combined each one
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  individually. That number stops people cold every
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  time I say it, and it should, because we do not
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  talk about flash floods the way we talk about
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  tornadoes. There is no dramatic radar footage
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  on the evening news every spring. They happen
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  fast, in remote places, and the people caught
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  in them often had no warning at all. That is
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  the problem we are solving today. I have spent
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  a lot of time in canyon country. The army put
• 1:50
  me in some demanding terrain, and I have done
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  my share of slot canyons since. What gets people
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  into trouble out here is not bad luck. It is
• 1:59
  a gap in how they understand the system. Once
• 2:02
  you understand it, this is a manageable risk.
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  Not zero, but manageable. So let's build that
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  understanding from the ground up. Start with
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  why the desert makes this so much more dangerous
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  than anywhere else. In most landscapes, when
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  rain falls, a meaningful percentage of it soaks
• 2:21
  into the ground. The soil absorbs it. The runoff
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  is gradual. In the desert southwest in summer,
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  the soil is baked hard, especially after a long,
• 2:30
  dry stretch. It absorbs almost nothing. Rain
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  hits it and runs off immediately. Not some of
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  it. Most of it. Now put that runoff into a landscape
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  that is nothing but slopes and gullies and washes
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  funneling toward canyon systems. Every drop that
• 2:47
  falls on 20 or 30 or 50 square miles of plateau
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  is being channeled toward the same low point.
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  Gully feeds a wash, wash feeds a canyon. And
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  because water runs faster when it is deeper,
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  less friction relative to its volume, the leading
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  edge builds into a wave. Then that wave hits
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  a slot canyon, and the walls take away any room
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  it had to spread. It goes up instead. Water levels
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  in a slot can rise 10 feet in seconds. The flood
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  carries rocks and logs and everything the watershed
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  has been holding onto for months. It does not
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  announce itself. In 1997, 11 people were killed
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  in Lower Antelope Canyon in Arizona. The storm
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  that killed them dropped its rain seven miles
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  upstream. At the canyon itself, the sky was clear.
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  The lone survivor was a guide who had swift water
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  training and recognized what the sound meant
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  before the water arrived. Seven miles away, clear
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  skies overhead, eleven people gone in minutes.
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  That is the thing everything else in this episode
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  hangs on. The weather at your location is almost
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  irrelevant. What matters is the weather across
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  the entire watershed above you, and that watershed
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  can cover an enormous area. In some canyon systems
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  in southern Utah, the drainage area feeding the
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  lower canyon stretches 50 miles or more. You
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  are not just checking if it is going to rain
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  where you are standing. You are checking an entire
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  region. This gets dramatically worse during monsoon
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  season, which runs roughly July through September
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  across the southwest. Most people have no idea
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  the desert has a monsoon. What happens is this.
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  Moisture flows up from the Gulf of Mexico. The
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  air gets humid by desert standards, and every
• 4:34
  afternoon massive thunderstorms build over the
• 4:37
  higher terrain. They are predictable in their
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  general timing. Mid -afternoon is when the instability
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  peaks and deeply unpredictable in exactly where
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  they hit. I have watched these storms build from
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  a ridgeline. They go from nothing to a full -column
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  thunderhead in under an hour. The anvil spreads
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  at 60 ,000 feet. The storm overdevelops, and
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  then it collapses, and all that water falls at
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  once over a small area onto ground that will
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  not absorb it. The Army trained me to read weather,
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  and what that training really teaches you is
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  that you cannot negotiate with the environment.
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  You can read it, you can plan around it, you
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  can respect it. You cannot argue with it once
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  the water is moving. The skill is not surviving
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  a flash flood. The skill is never being in one.
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  So... Here is how you actually manage this. Starting
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  before you leave, check the weather, but check
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  it correctly. A weather app showing your pin
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  in Springdale is not enough. You need to look
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  at the forecast for the entire watershed above
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  your canyon. For the Narrows specifically, that
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  means the high plateaus north and east of Zion,
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  not just the canyon floor. The National Weather
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  Service site lets you click around a map and
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  pull forecasts for specific grid points across
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  a region. Spend 10 minutes with it. Look at the
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  whole picture, not just your destination. Know
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  what you are looking for. A flash flood watch
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  means conditions are favorable for flooding to
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  develop. Respect it. Think carefully about entering
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  a canyon. A flash flood warning means flooding
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  is either happening or imminent. Do not enter.
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  Full stop, and if you are already in, get out.
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  Zion posts a flash flood potential rating on
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  the park's current conditions page. Check it
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  the morning of. If it is elevated, the Narrows
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  is not on the agenda. This is not a judgment
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  call you make standing at the trailhead, looking
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  at blue sky. You make it the night before, with
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  the forecast in front of you, before you have
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  driven two hours and invested a day. If there
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  is any meaningful storm potential anywhere in
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  the watershed, not just overhead, anywhere above
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  you build in your margin. The conservative call
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  in a slot canyon is almost always the right call.
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  The canyon will be there another day. That is
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  the perspective the place itself gives you when
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  you stand in it. It has been there for millions
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  of years. It will wait. What happens if you are
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  already inside and the situation changes? The
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  sound comes first. A low roar that does not quite
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  fit the canyon. Not wind, not thunder, something
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  lower and more continuous. You feel it as much
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  as hear it, a vibration in the walls and in your
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  chest. If you hear that and you are in a slot,
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  you move immediately. Not in a minute, not after
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  you check something. You move toward high ground
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  right now. The water is the next signal. If you
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  are waiting and the water goes from clear to
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  brown and murky, picking up silt and debris that
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  is upstream runoff entering the system. The flood
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  may be minutes behind it. Know where the high
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  points are before you need them. Slots have ledges,
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  alcoves, carved benches in the walls. Before
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  you enter any canyon, you are looking for these
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  on the way in. Every quarter mile, you identify
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  you're out. That habit from the Army, know your
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  way out before you commit to the terrain, applies
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  in a slot canyon as directly as it does anywhere
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  I have been. Some people describe a distinct
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  smell arriving ahead of the water, earthy, organic,
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  the debris of a watershed suddenly disturbed.
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  I have read enough accounts from people who survived
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  to take that seriously, even if I would not rely
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  on it as a primary warning. The smell, the sound,
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  the watercolor, these are all the canyon trying
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  to tell you something. Listen, if you are caught
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  and the water is already rising, go up, not out.
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  you are not outrunning a flash flood downstream.
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  The water moves faster than you do and carries
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  debris that would stop you. Get as high as you
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  can as fast as you can, hold on, and let it pass.
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  They rise fast and they drop fast. The initial
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  surge is your critical window. After the wave,
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  the risk is high water and continued debris,
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  but the worst of it is usually over in minutes.
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  Let me talk about the decision -making side.
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  Because this is where I see the most failure.
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  People rationalize. It is a human thing, not
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  a character flaw, but in a slot canyon it can
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  be fatal. I have watched smart people talk themselves
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  into bad decisions because they really wanted
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  to do the thing they drove four hours to do.
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  The investment. The planning. The group expecting
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  a great day. The sky looking okay from where
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  they are standing. None of that changes the physics.
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  The canyon does not care about the drive from
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  Las Vegas. If the forecast shows meaningful storm
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  potential in the watershed, the right call is
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  to do something else that day. Go to the east
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  side of the park, hike observation point. Come
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  back to the Narrows tomorrow when the forecast
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  is clean. The Narrows on a good day is one of
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  the more remarkable hikes in this country. I
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  mean that, and it is not worth betting your life
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  that the storm is going to miss the drainage
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  above you. The other thing I see is the group
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  dynamic problem. You are with people, everyone
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  has made the trip, and nobody wants to be the
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  voice that says, maybe we should not do this.
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  I have had to be that voice. It is uncomfortable
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  for about 10 minutes. In the other scenario,
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  where nobody says it, you end up in the canyon
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  when the water changes color. One person willing
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  to say, let's think about this, is worth more
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  than a full group nodding toward a slot canyon
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  with a bad forecast. Trust that instinct. Say
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  the thing. Practical rules to close with. Check
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  the weather for the whole watershed, not just
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  your location. Know the difference between a
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  flash flood watch and a warning and act accordingly.
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  Start early. The afternoon thunderstorm window
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  in the southwest is roughly noon to six, so mornings
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  are your safest window. Before you enter any
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  canyon, identify high ground every quarter mile.
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  If the water changes color or you hear a sound
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  that does not fit, move immediately, not in a
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  minute, now. And if someone in your group says
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  they are uncomfortable, listen to them. They
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  may be reading something the rest of you are
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  rationalizing away. This applies beyond the narrows.
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  Any slot canyon, any desert wash, any narrow
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  drainage in the southwest during monsoon season
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  carries this risk. The skill transfers once you
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  understand how a watershed works and what to
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  watch for. you carry that knowledge everywhere
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  the terrain demands it. Next episode is Yellowstone
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  Part 1, The History. The supervolcano underneath
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  it, the Nez Perce and Shoshone homeland that
• 11:42
  came first, the U .S., Army as the park's first
• 11:45
  rangers, and the near extinction and recovery
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  of the American bison. It is a long, extraordinary
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  story, and I have been looking forward to it
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  since we started this show. Noah links, the Zion
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  flash flood potential page, and a watershed reference
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  map for the Narrows drainage are all at wildlandsnews
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  .com. I'm Sean Spanauer. This has been Wildlands.
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  Know the land before you reach it. See you Thursday.