by Andy Selters
CONTINENTAL CLIMATES
The Canadian Rockies and the eastern European Alps (Bergalia and Tyrol) typify a continental climate: very cold in the winter with snowfalls that can come any time of yean The winters often bring only modest snowfall—just a few feet or less of dry powder—and, therefore, crevasse bridges can remain barely substantial into the early spring. But storms usually pass through from March through May, building bridges as the temperature gradually warms. Then, as in a maritime summer, melt-freeze cycles can alternately deteriorate and reinforce the snowbridges, or 24hour melting temperatures can just weaken them. Snowfall and rain are common too, keeping bridges relatively soggy and treacherous, especially at higher elevations. September typically brings an early onset of cold air and more stable (although quite broken) glacier surfaces, until occasional storms bridge the fairly open slots with light powder
POLAR REGIONS
The cold, dry climates of the polar regions generate glacier ice that almost never melts. The interior of places like Ellesmere and Baffin islands, Greenland, and Antarctica may receive only a few inches of snowfall each year But so little of this ever melts that these regions are mostly vast icecaps, by far the most extensive glacier terrain on the planet. Ice in Antarctica and Greenland accounts for a huge majority of the world's fresh water
Occasional warm summer days melt the surface some, but the overall mass of ice and polar temperatures assure that most of the melt-water only refreezes. Over centuries, this has created super-hard ice. In the extreme polar deserts you find light amounts of new snow blowing over glazed ice as old as civilization and as hard as granite. The sharpest ice screws and ice tools penetrate this stuff only under heavy persuasion. In these conditions, few snowbridges are strong enough to be trustworthy, though the ice is less active in these dry areas and so there are fewer crevasses. The most dangerous regions get a moderate amount of snow, enough to generate crevasse-forming motion and weak bridges.
SUBTROPICAL AND TROPICAL GLACIERS
The very high and extensive mountains of the Himalaya and the Andes have a wide range of climates. In general, the high altitude and high-angle sun of these mountains bring snow conditions that can fool a climber used to temperate glaciers. Snow deteriorating under an intense sun in the very dry air does not always turn slushy; rather, the moisture sublimates or evaporates. The snow structure weakens by becoming more airy and “rotten,” without the telltale sogginess of warm snow at temperate latitudes. Also, the intense radiation exaggerates the difference between north- and south-facing slopes.
The glaciers of Nepal typically extend from steep accumulation zones to 15 miles or more down the valley. The long ablation zones are covered with rock rubble that has fallen off the adjacent slopes. Hiking here can be a difficult stumble over debris that slides on the ice.
Two distinct seasons feed these glaciers. From June to early September, the summer monsoons dump a lot of relatively wet snow at the higher elevations, and from late December through March winter storms drop moderate amounts of cold, dry snow. During both the pre- and post-monsoon climbing seasons, melt-freeze conditions prevail and gradually open the crevasses. The surprisingly warm pre-monsoon season, right after winter's colder snowfall, can make for especially treacherous bridges. Somewhat cooler and shorter days in the post-monsoon season make the opening-up process more gradual. New snow can rebridge crevasses anytime during the two climbing seasons, especially pre-monsoon.
Farther northwest in the Himalayan chain, in the Karakoram, the monsoon season has little effect and the continental climate brings snowfall any time of year The very high elevations attract much more precipitation overall than in other continental ranges, however, and the winters are much longer and colder than in Nepal. So here flow the greatest temperate glaciers in the world, with many over 30 miles long. As in Nepal, the long ablation zones convey vast quantities of fallen rock. The big accumulation zones have proportionately large crevasses.
Spring and summer bring searing hot days, but the nights chill rapidly in the thin atmosphere. Therefore, radical temperature swings induce radical melt-freeze cycles throughout the climbing season. Unfortunately, periodic storms between clear spells usually add fresh snowfall, and so the accumulation zones of the Karakoram can be as treacherous as those in Alaska.
The Andes of Peru and Bolivia have glaciers of a more alpine scale, from 3 to 10 miles long. The climate here is markedly seasonal. The high-sun “winter” (September/October through March/April) brings easterly trade winds with snow virtually every day, while the low-sun “summer” climbing season (May through August) brings daily clear skies with occasional afternoon squalls. Intense melt-freeze cycles are quite predictable during “summer,” and the onset of the season gradually opens but strengthens the glacier surfaces. In these conditions, melt-water freezes into sub-surface ice, and so bridges can be even stronger than they might look to a temperate climber Bridges sag less than in temperate regions, however so they're less visible under snow. When an icy bridge gets old and “honey-combed” the ice can fail unexpectedly. The chance of snowstorms rebuilding soft bridges decreases farther south, and in Bolivia the dry season is particularly long and pronounced.
HEALTH OF GLACIERS
Glaciers depend on lots of snowfall for their “health,” and so their condition fluctuates with the climate. Even though numerous glaciers have advanced in recent decades, the twentieth century has been one of general glacial reduction almost everywhere in the world. Most glaciers in the Cascades and the Alps have thinned and receded. High routes that went over smooth glacial terrain in the 1950s are now complex with crevasses and seracs, or even require rock climbing.
The ancestors of the Baltis of the Karakoram drove pack animals over glacier passes to trade in Central Asia, but with thinner glaciers those trade relations are blocked by icefalls and rock cliffs. Andean ice faces climbed in the 1960s are thinning to remnant seracs calving over rock buttresses, and Patagonia's glaciers are now miles shorter than they were just a couple of decades ago. Near British Columbia's Mount Sir Sandford, in a spot where glacier ice ran 200 feet thick in 1900, a hut now stands in a meadow with a distant glacier view.
Perhaps the most dramatic contemporary recession has been in southeast Alaska. Glaciers that mariner George Vancouver saw calving at the outer coast 200 years ago now end 100 miles inland, across now-open Glacier Bay. This retreat accelerated in the last quarter of the twentieth century, so maps of the coastal area made in 1971 were seriously out of date by 1990.
This general retreat started before the Industrial Revolution, but the possibility that much of the recession is caused by human-induced global warming is distressing. Once again, glaciers seem to be contributing to our view of the world and our place in it.
OPENINGS
As soon as classes let out for the summer following my freshman year in college, I headed for the north side of California's giant volcano, Mount Shasta. It was my first glacier climb, and I was lucky to join two experienced partners. They gave me a middle knot to clip into along with instructions to keep the line snug as we traveled. We climbed a steep chute to the top on a blazing hot day, using “glacier cream” to hold our sunburns to the blister stage. I was thrilled with my first big summit and ready to take on more.
We were nearly back in camp, traveling on easy ground, when the guy up front seemed to fall to his knees. I paused, and the guy behind me shouted for me to get ready for a possible arrest. I laughed, thinking, “Yeah, right, he's really going to fall on a ten-degree slope.” But it was no joke, and I got a reprimand. I had no idea what a crevasse was or why the leader had suddenly sunk into the ground. He struggled up and we got to camp.
When they explained to me that the surface of a glacier is hollow in places, my eyes grew wide. I cringed at the thought of plummeting into one of those icy black holes. There had been no sign of a trap where he had fallen, just smooth snow. Worse, they said that it's typical that if you fall in very far you can't just climb out
, because the snow is loose and overhanging. Suddenly I had more questions than confidence, and I doubted the wisdom of going where we had just gone.
On the next trip, my primary goal was to rappel into a crevasse and practice ascending out. But even with that experience, the idea of hidden pitfalls anywhere bothered me so much I wondered if one shouldn't anchor-belay every step.
Descending a glacier on Imjatse, Khumbu Himal, Nepal
CHAPTER 2
PRINCIPLES AND PROCEDURES OF GLACIER TRAVEL
“[The crevasses] soon became more numerous and were ugly things to look into, much more so to cross…. The snow lay up to [the] edges and traveling became so insecure that we had to take to the ropes, and so, like a long chain of criminals, we wound our way along. In this mode we moved much faster, each man taking his run and clearing even broad crevasses if they crossed the direction we were traveling.”
—Henry Haversham Godwin-Austen,on
exploring the Karakoram for the Mustagh Pass,l860.
From When Men and Mountains Meet. John Keay.
It cannot be overstated how valuable it is to understand crevasses and snow if you hope to stay off weak snowbridges. But no one can judge snow perfectly, so the bottom line for the glacier traveler remains this: Where there's snow on a glacier there's a chance of plunging into a crevasse. It is impossible to say exactly how great this chance is, and the likelihood varies greatly with place and time. Therefore, with uncertainty presumed, partners on a snow-covered glacier travel roped together in order to stop each other's crevasse falls and to rescue each other This chapter covers the procedures for travel, and the next two chapters cover rescue.
Roped travel sounds straightforward, but it takes coordinated, alert teamwork for a team to travel efficiently. And only thorough preparations can knit a realistic safety net—a simplistic “rope up and go” attitude provides only a false sense of security. The preparations and considerations might seem overwhelming to a beginner; to the naive they might seem like burdensome rigmarole. But the procedures become almost second nature after just a handful of excursions.
BASIC ROPED TRAVEL THEORY
When we tie into a rope to hold falls through weak snowbridges, the premise is different from when we tie in to potentially catch a fall on steep rock or ice. To catch falls on steep terrain, we typically set up belays, probably with anchors that can withstand a substantial force, and only one climber moves at a time. But to guard against crevasse falls, the standard procedure is for ropemates to tie in at measured intervals along the rope, travel together, and depend on each other's readiness and ability to ice-ax arrest (discussed below). If a team travels with sound judgement and the basic procedures described in this chapter the potential force of a crevasse fall can be hard but not severe, and so partners can expect to stop falls without an anchored belay. However, it's crucial that climbers know when they are roped for crevasses, and to not carry this “roped together” system onto steep ground, where an unbelayed fall would only bring the whole team tumbling down together
Because crevasse falls rarely put a severe strain on a rope, it has long been accepted that approved “half ropes” of 9 millimeters (or even smaller diameters) are adequate for glacier travel.
ARRANGING MEMBERS: HOW MANY, HOW FAR APART?
Glacier travel teams function differently depending on the number of members, their experience, and how they arrange themselves on the rope(s). Other things being equal, a team's dynamic strongly correlates to how far apart members tie in, and thereby the distance between them as they travel. A greater distance between members means there's plenty of rope to span wide crevasses, little chance of one falling member pulling in another and more freedom to negotiate corners and zigzags.
However a shorter span has its own advantages. The most important is that a shorter span generates less slack—a crevasse fall on a long span can potentially be long enough to turn a trivial “punch-in” into a fall requiring a rescue. Also, in areas with dense crevasses, a shorter span is easier to keep perpendicular to the slots (discussed in greater detail under “Team Travel,” below).
The decision of how many people per rope and how far apart should also take into account what sort of glacier you're on, and what condition it's in. For travel on a medium-sized alpine glacier—such as in the Alps or British Columbia—with a typical degree of crevassing, a span that balances these factors is 30 to 40 feet (10-12.5 meters) apart. On small glaciers with minimal crevasse hazard it can be efficient and safe to carry less rope and put members just 20 feet (6 meters) apart. Big glaciers, like those in Alaska and the Karakoram, can have crevasses over 50 feet across, and so a 60-foot (about 20 meters) span can be necessary. With these factors in mind, let's summarize how teams of two to five members work.
“…if you do fall in a small [crevasse] your pole will fall across the walls and hold you up if you carry it in the right position.”
—Tom Lloyd during (unroped) first
ascent of Mount McKinley, 1910. From
The Sourdough Expedition.Terrence Cole.
THREE-PERSON ROPE TEAMS
Having three people per rope has long been the accepted minimum for a glacier travel team because, assuming the members travel with care, it virtually assures that two people will be available to hold a fall and carry out a rescue. Along with this reasonable degree of safety, three members generally can coordinate fairly easily. When three people travel on a typical alpine glacier, one member ties into the middle of the rope, and her two partners tie in about 30 feet away on either side. On a 50-meter (164-foot) rope, this leaves about 50 feet of spare rope for both end members to carry. The middle member connects to the rope with a bighted knot (either a figure eight or butterfly knot) clipped to two carabiners on the harness, at least one of which is a locking carabiner The end members will need to coil and carry the extra rope, and can tie in using one of two different methods.
The first method is simply to clip in just like the middle person and coil the slack, wrap and hitch the coils together with the rope's end, and stow the extra rope in the pack. The other method is to tie in to the end of the rope with a figure eight retrace, wrap coils snugly over the shoulder, and tie in with the “kiwi coil” method (see appendix). This method is convenient for a transition to fully extending the rope for technical climbing, because the end members are already tied to the ends of the rope.
Whichever the method, the “spare” rope can be crucial during rescues.
Whether on a long or short span, teammates of differing abilities should arrange themselves so that the person who goes first is the one most practiced at routefinding and judging crevasses, and the person with the least experience travels in the middle.
FOUR-TO FIVE-PERSON ROPE TEAMS
A party of four or five can choose whether to travel on one rope or two. The advantages of the entire group traveling on one rope include more person-power to hold falls and less rope weight for each person to carry. In addition, if a party of four or five includes a couple of novices, it can be wise to “hide” them in the middle of a single, more populous rope than to “expose” them on the end of another rope.
The drawback of a populous rope team of four or five is that they will generate more hassles in coordinating pacing, turns, rest stops, and crevasse crossings. Also, a party of four or five that divides itself into two rope teams can find that the second rope gives them more options in the event of a complicated rescue (see chapters 3 and 4).
In summary, a team of four or five must decide what are the primary concerns. If a glacier is relatively small with few crevasses, a single rope for four or five provides a reasonable system with less overall gear to carry. Also, if the glacier and its crevasses are large or in a dangerous condition, if you have heavy packs, or if some members are less experienced, it can be wise to prioritize for holding power and travel all together But if all the members are experienced, and if there is bound to be some complicated terrain that you'll want to handle efficiently, it's
better to split four or five members into two rope teams.
TWO-PERSON ROPE TEAMS
Should a party of four or five divide itself into two rope teams, at least one of those will be a two-person team, and that pair will depend on just one member to hold the other's crevasse fall. This is a reasonable chance to take in most cases (exceptions are discussed under “Holding Falls” later in this chapter), as unless a pair travels carelessly or in particularly dangerous conditions, a single climber should be able to resist the force generated by a crevasse fall. However, though a single climber can expect to hold a crevasse fall, for that single climber to rescue a fallen partner is another matter Therefore, all but very experienced two-person rope teams will depend on help from another team in their party to at least anchor the rope should one of the pair break through a snowbridge. Consequently, a party with a two-person rope team should take extra care to keep another team reasonably near to the roped pair. Both members of a roped pair should tie in an equal distance from the middle of the rope, and they should carry more extra rope than the span between them. They may want to add stopping power to their rope by adding “drag knots” (see Chapter 4).
Figure 2.1 Recommended rope spans between team members
