Prof. Hike: Don't Get Caught in the Dark

I recommend that you try hiking at night, but only on purpose. Most of my night hikes were accidental—a result of getting lost or behind schedule. Only one trek—descending the New Hance Trail into the Grand Canyon on a full-moon night—was actually part of the plan. This week I’ll explain how to avoid accidental night hikes and what to do if you get caught in the dark.

Just in case you need a reminder, here’s the typical night-hiking scenario. Footsore and weary, you trudge along a trail watching the sun vanish behind a distant ridgeline. Your car is five miles (you think) ahead, and you’re almost out of water. Crinkling in your pocket is the empty wrapper of your last trail bar. A chilly breeze kicks up, and the undergrowth flanking the trail recedes deeper into shadow. As the light fades, you notice the brightly colored leaves wane into monochrome gray. You stumble over hidden roots and rocks as your forward progress becomes more about feeling than seeing. Something rustles the leaves behind you. Is it the wind—or a mountain lion coiling to make a neck-snapping pounce? (Have a good night-hiking story of your own? Describe your own misadventures in the comments section below.) 

OK, you get the picture. When you’re not prepared, hiking after dark can be frightening. After all, if humans were meant to be nocturnal, we’d have huge eyes like lemurs and echolocation like bats. But since we’re pretty helpless in the dark, here are three tactics to keep inadvertent night hikes off your itinerary.

Know your time limit

It’s 6:10 p.m. Do you know when the sun will set? Find out before you leave for a trip. Newspapers print daily sunrise and sunset tables on the weather page, or check the website www.sunrisesunset.com. Most GPS devices also deliver accurate sunset estimates, and smartphone users can download free apps that determine the time specific for your location. Knowing the exact minute the sun disappears below the horizon is helpful, but a ballpark figure is just as good. And remember that these times constantly change. In October the sun sets one minute earlier each day in the United States and two minutes (or more) earlier in Canada and Alaska.

Bring a light…always

Packing a headlamp for a day-hike might seem excessive—unless it prevents a shivering night in the woods. Any search-and-rescue team can confirm that most lost-hiker scenarios are either initiated or complicated by nightfall. If some of those missing hikers had packed a headlamp (as well as a map and some common sense), they might have been able to self-rescue—saving time, money, and personal embarrassment.

In general, lost hikers should stay put, conserve energy, and wait for help to arrive. Stumbling through the woods at night without a light is the second-worst course of action (after panicking). You could easily injure yourself, become more lost, or miss obvious clues like a trail sign or road. But if you have a headlamp and some notion of your present location, hiking out might be safer than hunkering down until morning. In most situations, using a headlamp will give you several more hours of safe hiking time to become unlost. Maybe there’s only a 10 percent chance of becoming lost on a trip, but there’s a 100 percent chance that darkness follows day. Carrying a three-ounce LED headlamp (spare batteries aren’t a bad idea either) is very lightweight insurance policy against that certainty.

Plan realistic mileage

Getting caught after dark is more often the result of poor planning than bad luck. Can you start a nine-mile summit attempt at 2:00 p.m. and finish before sunset? Maybe you could in Alaska in June (when the sun never sets), but not in New Hampshire in November—even if your trail name is Flash Gordon. Most hikers move at 2 mph or less, especially after adding rest breaks and meals. Plus, groups naturally move slower than individuals. So plan daily mileage goals based on hiking speeds between 1 and 2 mph, and give yourself a safety margin of an hour.

Nature gives you a little break, too. You’ll often get an extra half hour of usable twilight after the sun sinks beneath the horizon. This afterglow will disappear faster, however, if you’re on the eastern slope of a mountain or stuck at the bottom of a narrow canyon.

When night falls… 

Despite the best precautions, you can still find yourself hiking in the dark. This happened to me last November on a Shenandoah trip when my crew got caught after sundown on the eastern slope of high ridge. The last mile of trail before our campsite seemed three times longer due to many darkness-induced false hopes and ankle-twisting stumbles. This experience reinforced four night-hiking tips I want to share with you:

1. Delay turning on your headlamp until it gets really dark. This advice sounds counterintuitive, but it works because your unassisted eyes function better in fading light than they do in the harsh glare of a headlamp. It takes 30 minutes for your pupils to adjust to see in darkness. Any flash of white light, like someone accidentally shining a headlamp in your face, shrinks your pupils and resets your night vision’s 30-minute clock.
2. This fact leads to a second piece of advice: When hiking in a group, agree to keep everyone’s headlamps off until it gets really dark. One person with a light will ruin the night vision of everyone else.
3. Did you ever notice you can see better at night using your peripheral vision? That’s because rod cells—your photoreceptor cells for low-light conditions—are located at the edges of the retina. To see better in the dark, swing your head from side to side to engage the peripheral rod cells in scanning the trail ahead of you. Yes, you’ll look odd, but you’ll see the trail much better.
4. Let your other senses take over. Does the map indicate a stream is off to the right? You can’t see it, but perhaps you can hear it. And if you notice water sounds on your left, you better double-check that map. Likewise, listen to the feedback from your feet. After a few minutes of hiking in the dark, your boots will learn which shadows indicate safe footing, and which might yank your ankle. Let your non-sight-based instincts take over, and you’ll have an easier and safer time moving in the dark.

Lights out for this week. Tune in next week to find out Where the Wild Things Are (and Aren’t)