SLUFF MANAGEMENT

Jim Conway & Mark Newcomb, Senior Guides, Valdez Heli Ski Guides

ABSTRACT: Since the first World Extreme Skiing Championships in Valdez in 1991, the Chugach Rangearound the Thompson Pass area has drawn thousands of skiers seeking steep powder and adventureskiing. The spring season often provides "windows" of stability which allows skiers and snowboarders topush into steep, technical, and exposed terrain. The steepest slopes now descended by heli skioperations in the area range from 40 to 60 degrees. While these "windows" of stability may have lowhazard in terms of slab potential, sluffs and small point release avalanches remain a hazard. Over the lastfive years the staff at Valdez Heli Ski Guides have observed the interaction of skiers/boarders with sluffs invarious terrain scenarios. The term "Sluff Managemenf was developed to describe the various techniquesof avoiding and managing this hazard.

The presentation will describe the types of terrain and snowpack where sluffs become a significant hazardthat needs to be managed. It will also review the recent evolution of powder specific skis and snowboardsand how this relates to managing sluff hazards. Real life examples will be used to represent variousscenarios depicting a number of Sluff Management techniques. Many of the techniques to be reviewedhave proven significant in reducing the risk of an incident negotiating the steep terrain in the CentralChugach area.

Keywords: Snow Slides, Avalanche Tracks, Avalanche Triggering

1. Introduction:

Due to advances in equipment, hype from themedia, and changes in attitude, the demand for thesteep skiing experience has increased over thelast ten years. While not a mainstream activity,steep skiing has certainly risen above the "fringesport" category within the skiing community.Concurrent with this development was therediscovery of Alaska's Chugach range as apremier steep skiing center. The first World"Extreme" Skiing Championships in 1991 exposedmany avid backcountry and hard core skiers to theareas potential. Within three years the firstcommercial guiding operation was established.Now, there are four commercial heli ski operatorsin the Valdez area, three of which specialize in thesteep skiing experience.

At Valdez Heli Ski Guides, this evolution hasresulted in an economically viable guide operationthat caters to clients who desire an adventureexperience. The ability of the client varies from thewell conditioned expert to world class skiers andboarders. Even the least experienced clientspossess

the athletic ability and competence to negotiatesome very challenging terrain, but they may nothave the necessary mountain or snow skillsrequired. A great deal effort, beginning with athorough safety briefing, is devoted to educationon avalanche hazard, glacial travel, and respectfor the mountain environment. For the clients,guide direction and coaching is critical for reducingthe risks. Terrain is selected for each client basedon their skills, experience, desire, and ability tofollow the guides recommendations. Clients startoff on easily manageable slopes and graduallyprogress into more challenging terrain ("TerrainProgression").

Once stability has been established, andsuitable terrain has been selected, the hazardmost commonly encountered on steep slopes issluffs. The guide staff, through the use of basicbackcountry protocols (Le. skiing one at a time),observation, and some hard leamed lessons, hasdeveloped a method labeled "Sluff Managemenf.The goal is to reduce one of the many risksinvolved in traveling in a winter alpine environment.

2. Defining a Sluff:

Corresponding author address:1579 East Sherleen Circle, SLC,801-278-5534, FaxDepthhoar@AOL.com

Jim Conway,UT 84124801-272-0183

For the purpose of this discussion, a "sluff' will beconsidered a small loose snow avalanche. Oftenthe sluff will be the result of a series of pointreleases in the starting zone. The depth of the

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layer, for manageable sluffs to which this paperrefers, can range from 3 to 15 cm. Skiable slopeslikely to sluff range from 40 to 60 degrees.Observed speeds, estimated in the field, rangefrom 5 to 25 meters/second. The density of thesnow involved is typically 5 to 15%. The snow isnew snow, decomposing precipitation particles, ornear surface faceted crystals. The highest potentialinvolves near surface faceted snow. Sluffs havebeen observed up to two weeks after the last stormevent on the steeper slopes. The father out from astorm event, the more likely the sluff layer iscomposed of facets. Most of these events do notresult in significant deposition in the runout (0.0 to0.4 meters).

3. The Need for Management:

Although burial is a possibility, basic terrainselection usually removes this risk (Le.: avoidingterrain traps). The hazard comes from the sluffcausing a high speed fall down steep, and in somecases, exposed terrain. Injury due to trauma mayresult. This may be caused by impact with otherobjects or simply over stressing the body in aviolent tumble. The slopes descended vary from500' to 2000', and range from 40 to 60 degrees.Exposure may consist of cliffs, seracs,bergschrunds, or crevasses. Bergschrunds lyingbelow many steep faces are the most commonhazard, especially when the gap is wide, or thedownhill edge of the gap is higher than the uphill("Innies"). The ultimate goal of sluff managementis to avoid interaction with a sluff event.

4. Sluff Management Techniques:

Avoidance by Speed - This can be describedsimply in two ways. Go slow enough to stay abovethe sluff in the starting zone. Or, go fast enough tobeat it through the runout zone. Obviously thetechnique used depends upon the skiers abilityand snow quality.

Avoidance by Terrain - Proper terrain selectioncan eliminate exposure to a sluff event. Thesimplest technique is to ski off falline to one side inthe starting zone. A variation of this is to ski downan appropriate number of turns (depends on thedynamics of the slUff) then traverse off to one side,out of the sluff path, and begin tuming again. Aslong as there is enough room laterally, wholeslopes can be descended using this technique.Another method is to ski slopes with a doublefalline so the sluff is constantly moving downhilland away. Finally, spines (steep snow ridges) are

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another good terrain feature, as the snow falls toeither side and away from the skier. The spinemust be big enough that the skis are not near theright or left edge of the spine where it meets thesluff path. A skier must also be alert if a spine endsat a point where the sluff path on either sideconverges. In all cases, care must be taken toavoid terrain features which enhance the sluff,such as gUlly bottoms and narrows.

Figure 1. Senior guide, Dave Swanwick makes use ofa spine to isolate himself from his sluffs on a 55degree face..

Avoidance by Combined Techniques - Oncomplex terrain, combining the above techniquesis the best way to mitigate the sluff hazard. Theirare countless variations of speed and terrain usethat can be successfully executed. The most basictechnique is to ski down to an Island of Safety,stop, wait for the sluff to pass, then continue. Anecessary skill for effective use of the combinedtechnique, is the ability to look up hill while skiingand track the progress of the sluff (also known asthe "Chugach Look").

A common scenario is to aggressivelydescend in front of a sluff, then as the skierobserves it catching up, he pulls off onto a slopewith a new falline and drainage. The original sluffcontinues down the first drainage while the skier

has transferred to the new drainage. A skier mightjust as easily ski up onto a spine or a side slopewith a double falline, watching for the sluff to passbefore reentering the original falline. A number ofthese maneuvers may have to be incorporated intoone run. Obviously, this is a more advancedtechnique requiring careful study of the terrainalong with mental and athletic skill.

Ski Cutting - Ski cutting is probably the mosttraditional method of controlling sluff activity. Inmany cases it will serve to eliminate the chance ofsluffing during a run. On the other hand, enoughloose snow may remain to create a substantialhazard, especially on the steepest slopes. But theexperienced steep skier may be reluctant to cutslopes for aesthetic reasons. This might be· for thepure powder experience or a film shoot. Where theskier is confident in his ability to negotiate theterrain and sluff paths, he may prefer to deal withthe sluff during the run, rather than control it aheadof time. The guide, through communication withthe client, determines what is advisable in eachsituation.

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Figure 2. Skier Eric Pehota cuts above a 50+ degreeface before descending. In spite of this cut he will stillneed to be alert for additional sluffing on this steepexposed face.

6. The Sluff Management Plan:

From the straight forward run descended by askilled but unpracticed client, to the complex linesof a world class skier or boarder, a sluffmanagement plan is the key to reducing risk. Asluff management plan is the result of careful studyof the terrain , snow conditions, skiers ability, andcontingencies. It puts together all of the techniquesdescribed above into a comprehensive plan. It iskey that the client is thoroughly briefed on his lineand options before he begins the run. It can be assimple as pointing out a recommended line; or ascomplicated as developing a plan that incorporatesall of the strategies above. The guide will point outthe potential sluff hazard to the client and willdevelop and/or approve a plan. A guide mustcarefUlly consider the clients line and be confidentthat he can execute it. If there is any doubt, a moreconservative line should be selected.

In situations where accomplished athletes dropbig complicated lines, time must be taken tothoroughly study the terrain and snow. The groupmay land adjacent to the slope and study it, ormake use of Polaroid snapshots. Most guides usethis opportunity to educate clients about hazardsand strategy. For each big descent it is prudentthat the guide works with the pilot and other skiersto come up with contingency plans in case of anincident. It is important to note here the standardpractice of pointing out the hazards and preferredline to an average client, versus the extensivepreparation involved in setting up a major descentby a world class athlete. The more complex thedescent, the more dynamic the plan needs to bewith options based on forecasted contingencies.

6. Conclusions

The techniques for sluff management havebecome more complicated due to two relativelyrecent events. One is the popularity ofsnowboarding and especially freeriding. And theother is development of wide high performanceskis designed specifically for fast high performancepowder descents. Snowboarders took the lead onestablishing how fast steep terrain can bedescended in powder conditions. But in the pasttwo years high performance fat skis have allowedskiers to adopt the same aggressive 'out in front'sluff management tactics. Controlled ski descentswith speeds from 40 to 60 miles per hour havebeen witnessed. In the past, the primarybackcountry user was most likely on narrowwaisted skis. The limitations imposed by thisequipment usually forced the skier to descend

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slowly and deal with sluffs high in the starting zone,staying high enough where the forces are lesspowerful. Now with the higher speeds allowed bysnowboards and fat skis, the rider has the potentialto be affected by the sluff much lower in the trackwhere the forces are much greater. The newtechnology, even in the hands of the averagebackcountry skier or heli ski client, has exposedeven more users to this hazard.

The staff at Valdez Heli Ski Guides has had astrong measure of success using the techniquesdescribed above. Fortunately, to date there havebeen no serious incidents as the result of a skier orguide being involved with a sluff. The practice ofthe techniques described in this paper clearlyreduce the risk of an incident.

Figure 3 to 5. Valdez Heli Ski Guides Owner/OperatorDoug Coombs descending a 45 to 50 degree face, 3days after a Bcm snowfall. Doug combined a numberof techniques to formulate his sluff management planfor this run. He is watching the progress of the sluff onevery tum and will cut skiers right when the sluffapproaches. He stays high and to the skiers right untilthe sluff passes, then back into the falline and throughthe next narrows. This type of line demands a highlevel of athletic skill and mental awareness, and isreserved only for the most experienced.

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