Feature

winter/spring 2000

Steeps and Sluff Management

by Bill Glude ‘The Avy Dude’

In the last ten years, descents of seriously steep 45°-70°plus runs have become more common in the Alaska Coastal ranges. Fat and shaped skis and snowboards--combined with strength, attitude and technique--have enabled pioneering snowboarders and skiers to descend terrain previously thought of as the province of climbers.

Like climbing, riding steeps is a high-risk activity. Steep, exposed lines carry a certain unavoidable and irreducibly higher risk than the gentler slopes.

Magazine photos and videos may make it look like the top professional riders drop into these lines casually, but each shot takes a long time to set up and safeguard. Extensive snow studies, analysis of the relative hazards of different lines, Polaroid photos and radio communication during descent are common precautions--and it is still dangerous work!

There are a number of ways to reduce the risk when descending steep runs. Taking the time learn a few things is a good thing to do for yourself and for your buddies when you’re out riding the steeps.

Be aware of unstable cornices.
Rider (Axel Pauporte)
Photo by Scott Sullivan

Reduce Your Risk

Reduce your risk by following a few safeguards. Maximize the odds. Here are some hints:

  1. Check the snow conditions. Begin with careful testing on gentler runs and small steep test slopes. Do observations, probing, slope tests, and pits. You do not want to be on sluff-prone terrain when slabs are likely! Wait for the right day! Be patient. If today is not the day to go big, go ride gentler stuff or shoot a kicker or cliff drop with a stable landing. Timing is everything.
  2. Fitness and Solid Technique. Make sure you’re fit and ready to pull off advanced maneuvers. Practice the basics and develop your steep skills progressively. Give the terrain the respect it deserves or the steeps will slap you hard!
  3. Develop your ability to jump. Jumping is an important safety skill in sluff-prone terrain. If you can handle moderate drop-offs or ramps as they come at you, you can travel rapidly through steep or narrow sections, where you don't want to hang around.
  4. Have escape route and alternate lines in mind. One turn or traverse where you skid downhill a bit more than planned can put you onto another line in a split second. Have your alternates in mind. Retreat uphill in steep terrain may be extremely difficult or impossible. This is one reason guides need ropes. A rider can be pinned above a too-big cliff.
  5. Beware of unstable cornices! They can be more tender than you realize and break off farther back than you may imagine. Watch for them while unloading on or approaching ridges. Assume any snow-covered ridge overhangs until proven otherwise. When jumping, look for the cornices with good support, not the overhanging ones, and a stable landing zone. Drifts and windlips are more-reliably stable launching ramps.

Test snow pack.
Manage Your Sluff
  1. Don't descend steep sluff-prone terrain when slab avalanches or large sluffs are likely. Thoroughly check out stability on lesser slopes first. Manageable sluffs are dry, no more than 3 to 15 cm (1" to 6") deep and leave deposits less than 40 cm (16") deep. Large sluffs are as powerful and dangerous as slabs. Don't mess with them.
  2. Remember that sluffs may trigger slabs even when slopes don't fail when ridden. The sluff can add more rapid load and stress to the snowpack than a rider.
  3. Consider sluffs inevitable on slopes steeper than 45° in soft snow. The snow may not sluff, but you should have a plan in mind if it does. In really loose or sugary snow, 40° slopes may sluff, but sluffs slow down and lose energy when the slope shallows to 40° in most snow.
  4. Sluff follows the hollows and depressions in the slope and spreads out thinly on "bowling ball" shapes. Where thin, it may be rideable. Where deep and powerful, it won't be.
  5. Know where your sluff is at all times! Look back uphill (called the "Chugach Look"). This is easier for toeside snowboarders. Skiers should practice a bit or track their sluff by its shadow if the sun is at the right angle. Just be sure you really know where the snow is.
  6. If the sluff is catching you, use "Islands of Safety" as places to stop while it passes. Pull up under on a protective terrain feature. Pull out to the side, preferably under a bump that will divert the sluff and protect you, or pause on top of a spine, bump, rib, or rock outcrop.
  7. Ski cutting. The traditional sluff management tool is to cut quickly across the top of the run, skidding and bouncing to release the sluff; then descend behind it. This may or may not clean out the slope, and it may or may not meet aesthetic desire for untracked snow.
  8. Avoidance by speed. This can be done either by going slowly enough that the sluff runs ahead of and below you, or by going like hell and not falling. While top riders often pull off the latter method, remember that you must be rock solid and confident to do it, and that even the best will sometimes fall. What are the consequences if you do?
  9. Avoidance by terrain - Keep working toward one side of the slope. Cut consistently left, or right, on every turn or every few turns so the sluff goes down the slope you have just left. You can pull to the side and pause, if necessary. This method works best on large, featureless slopes.
  10. Avoidance by terrain - Work double fall lines. When there is a side slope to the terrain, get up on it. The slope may fall away to one side, so work the high edge. In a chute, you may be able to stay up on one side while the sluff runs in the bottom.
  11. Avoidance by terrain - Work spines and ridges. The sluff will fall to either side. The spine must be wide enough for turns without getting boards caught in the sluff. Opposite sides of the spine are different aspects, and may have radically different snow and stability. Most spines form because snow builds up above a rock outcrop, ice chunk, or other obstacle. When your spine ends, can you jump the end piece, bail off the side, or pause on top? Sluff will be flowing on both sides. Will it spread out thinly enough to ride through once the channeling effect of the spine is gone?
  12. Avoidance by terrain - Change drainages or get up on a side slope as the sluff passes. Descend aggressively, bail as necessary. Use combined techniques to put together a do-able line. This is an advanced method.
  13. Avoidance by terrain - Watch the choke points! Places where you go through a narrows, leave a spine, or drop under any sluff-collecting feature will be the cruxes of the route. Either avoid the sluff-enhancing features, or time your passage so you are well ahead of or behind the sluff.
    14.

Test snow pack.

Sluff Management Plan
  1. Study and practice these techniques. Understanding them is the starting point, but it will take practice to really learn how to use them.
  2. Scout the runs. A simple flyover may suffice for some, others may require shooting Polaroids or landing on or climbing to a viewpoint to study and develop the plan.
  3. Scope everything out thoroughly. A landing with a view, where the run can be discussed at length, is preferable. Polariods and flyovers may also be necessary. Evaluate and discuss hazards and strategies. Identify escape routes and alternates. Some skilled riders are very big-mountain savvy; others are totally new to it. Regardless of experience level, the combined efforts of several brains will yield observations and options one person would not come up with alone. Plan and communicate freely. Use radios, but beware confusion - designate who communicates what just prior to and during run. Consider whistle signals. Have an emergency plan in mind, and have your pilot standing by in case of need.
  4. For people new to steep backcountry terrain, keep it simple. Be sure of your party's abilities first, and work through a progression from easy to more difficult situations. Clearly identify hazards and options. Don't push others. Let them choose the risk level they can comfortably handle.

Look at conditions area wide.

This article uses many ideas from Mark Newcombe, Jim Conway, Tom Burt, Jim Zellers, and the Out of Bounds heliguides in Juneau. Thanks to all of them.

Bill Glude is a professional avalanche consultant, instructor, forecaster, heli-guide and snowboarder living in Juneau, Alaska.