Concern 3: Snow Hazards To Watch Out For

Mountain Education Resources
Concern 3: Snow Hazards To Watch Out For

As you leave Kennedy Meadows and head on up toward the High Sierra snow pack, there is usually a lot of hype and anxiety about what is ahead, how much snow will be up there, will it slow me down, and how dangerous it will be, really. Much of the practical side of all this can be garnished from reading prior hiker’s journals to glean what, exactly, they went through and how they delt with it. As you’ll find, some are experienced and ready for it, knowing what to bring and do, borne out of earlier practice, while others are not as prepared and discover setbacks like not enough food, injuries, unnecessary equipment, slow progress, over exposure, dehydration, fustration, and disillusion.

We are here to assure you that with a little preparation for the realities of hiking on snow through the Sierra, based on the accounts of those who have done it, and with a little skills practice necessary for safe snow passage, acquired before you started your journey, you’ll get through just fine.

By far, the first hazard is your own attitude. If there is any question in your mind regarding your safety, remember the acronym, STOP, which stands for Stop, Think, Observe, and Plan. There are too many unforeseen variables in the wilderness to be of the mind that you are invinceable, there’s nothing out there that will be a problem, or that you can handle everything. You may sail right on through all your trials without a problem, but never be so naive to assume you always will. Have a plan that includes the realities of the trail, then have a backup.

Learning to STOP is especially relevant when considering the safety of the creek crossing before you, your next greatest hazard. You do not have to cross the roaring creek where the trail does, nor even right then. STOP, drop your pack, and consider your options up and down the creek. Try not to cross it alone. If you can’t find a dry route over it on rocks or logs, keep your shoes on and wade through it when it has less volumne, in the morning. If you can not wait, find a shallow crossing out of the whitewater, as free of submerged rocks and trip-able obsticles as you can find, and cross with the help of others, side-by-side, or with a strong stick as a third leg for support downstream. Change clothes immediately on the other side and continue on, drying out as you go. (We have talked about creek crossing techniques at length in other topics).

Timing your ascents/descents is of vital importance to your safety and enjoyment of the snowy sierra and, thus, is your next hazard. This one consists of three or four specific concerns: traction and falling, downhill post-holing, spring avalanches, and route selection.

As we have described elsewhere, ice or simple surface hoar can be very slippery early in the morning. On the flats of an approach, there is no big deal, except in and out of suncups and assorted wind wells, so it’s not much of an issue until the ground starts sloping ahead or beside you. Traverses can be particularly tricky in soft-soled shoes that do not have much traction in snow nor can hold a hard edge into the hillside. On the climb up to a pass in the morning, be aware of your balance at all times. Kick in footholds with every step as necessary. Stay close to the trees and exposed rocks for more stable snow. Do not switchback on steep climbs, but, rather, go straight up. Always have your ice axe or your self-arrest pole in your uphill hand. Descents are even more hazardous. Drop straight down wherever possible by plunge-stepping heel first slowly, self-arrest device at the ready. (Know how to self-arrest and have practiced with your pack on, for obvious reasons).

It is best to time your ascents for the mornings, have lunch on top, and descend before the snow gets so soft that you start postholing. Although this means that you will have to deal with creek crossings at their height in the afternoon (if you’re trying to do two passes in one day), you could consider slowing down your pace and camp at the creek to cross it in the morning and begin your next climb. Beware of afternoon snow descents from passes where your plunge-steps sink in to your knees or deeper. If you are not careful with your top heavy balance, you could lose it, falling forward, not be able to pull your leg out of its hole, and seriously torque your knee as it is leveraged against the surface ice, while you try to prepare yourself for a quick self-arrest, head downhill.

Keep in mind that spring avalanches do occur, so look for them around you as you hike throughout your day. If you see an old one near your route, the temperatures and conditions are ripe for more. Avoid slopes between 20 and 40 degrees of angle. Look for trees who’s branches are missing on the uphill side (taken off by prior slides). Watch for slopes where there are only little, short trees or where the trees have been pushed over during the winter. Keep in mind that the flats aren’t safe if there is a cornice nearby that could fall in the heat of thaw and start a slide below it, on the hillside above you, and come down to you. Always be aware of the temperature and humidity of the snow beneathe you (how stabile it is) and where the overhanging cornices are that could drop.

Your choice of route can seriously minimize all these concerns. Following valleys or ridges and staying in the trees or on the rocks is safest. Beware of soft snow bridges over creeks in the spring (a famous backcountry ranger, very experienced, died when the bridge he was on collapsed and he was swept under the snowpack and drowned, to be found three years later). Climb straight up or along the tree/rock edge of the approach and descend the same way before the afternoon post-holing starts.

Other cautions and advice: Wear serious lug-soled boots for ankle stability and traction assurance. Do not use crampons unless trained. Walk as far as you can before you start post-holing, then plan to be below the snowpack and on dry trail. Listen for noises underfoot, like the sounds of moving water or the hollow, “woompf” sound of a compressing snowpack that might be ready to slide. Be able to recognize in advance when the snow conditons are such that you need to have your ice axe at the ready (if you are using self-arrest poles, this isn’t a concern because they’re always in hand). There’s nothing worse than realizing you should have stopped and removed your axe from your pack before crossing a risky snowfield but didn’t, then you slipped and fell out of control into a tree or rocks below. Don’t learn the hard way.

Other hazards are to watch for submerged hazards like fallen tree trunks and rocks. When you step next to them, you may plunge alongside scraping your leg or twisting your ankle or knee. Because they absorb radiaton through the snow from the sun, the snow around them melts away leaving an often sizeable air space for you to step into. Always go around or step on top of them. Be aware of buried trees, as well, for the same reason. In general, look for bumps in the snow that don’t follow the slope of the ground; be suspicious of them. Stay away from wind wells around trees (don’t fall in) and from submerged tree branches (easy to posthole into and through them!). Go wide around buried and partially buried trees.

When you want to cross a snow bridge, go upstream and downstream of it to see under it and how thick it really is. Use your hiking stick to probe through it for soft snow as you cross. When you walk alongside a lake or creek, don’t assume the snow is strong, listen for moving water underfoot (inflow or outflow streams), and keep an eye above you for cliffs that might have cornices which could fall toward you. When you dip into them for water, be certain of your footing, preferably on dry ground.

Basically, you’ll be safer travelling over snow when you know the rules of the game (what to watch out for) and review them constantly as you go to minimize your risks. If there is any question, STOP.

Practice your snow travel techniques before you start your thru hike. Attend classes and presentations, read journals, and take skills training courses. Most of all, get out there and hike in the conditions you expect to find along the trail. Test yourself, your gear, and your food. Find out what works for you and don’t assume anything. Yes, you’ll learn as you go, as long as you don’t run into a problem before you’ve learned how to deal with it. Yes, you can improvise, if you have the resources of prior experience with similar situations. Know what you can do and in which conditions you need training. When you’ve prepared yourself for all this, you’re ready for your hike-of-a-lifetime!

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