When heading into the mountains, it is important not only to hope for luck, but also to understand the nature of the slopes. We look at how knowing the mechanisms behind rockfall helps minimize risks, and why a person against the backdrop of a mountain is merely a dot — which means that the main danger often lies not in the elements, but in one’s own overconfidence.
Remember: mountains are rock, ice, and snow
As Vizbor put it: “A mountain is the sky covered with rock and snow.” And all this substance is constantly breaking down. Ice falls or collapses — ice avalanches. Rocks fall or fly — rockfalls… Not to be confused with icefalls: an icefall is simply a pile-up of ice or a heavily broken glacier, where something also sometimes — in fact, always — breaks off, collapses, or crashes down, producing an ice avalanche, that is, flying chunks of ice… In terms of impact, it is the same as a rockfall.
Rockfalls are one of the risk factors for those who go into the mountains
And it must be said that understanding how they form can, in general, help ensure safe passage through potentially dangerous sections. At the same time, we must not forget: on a slope, we are a negligibly small quantity, so in most cases the probability of being hit is still significantly lower than the probability of a miss.
So what causes rockfalls? There are only 5 reasons:
– thawing and freezing of rock terrain — water on it or inside it;
– melting of glaciers or icy slopes containing rocks;
– rocks dislodged by people;
– an earthquake;
– the time has come.
I think it is clear that the last two are fairly rare and unpredictable events. So all that can be said about them is: they do happen. With earthquakes, you can still get some kind of forecast, but in my own practice we only found out afterward that one had occurred. And I have never been caught in rockfalls caused by an earthquake. Or I do not know that I have. It must be understood that the result of an earthquake may be a large volume of rock and debris flying at you. Or a very large volume — it may also be small, but we are not considering small or distant cases here. And it can happen at any time. Taking cover, if you are not already in a shelter, is impossible — there are too many ricochets, and a backpack will not save you. Of course, you should still cover yourself. At least with a backpack. But… In other words, it is better not to get caught in such rockfalls. It is practically impossible to build any tactical plan for passing through them. Either you do not go into seismically active areas at all — which means not going into the mountains at all — or you go, keeping in mind a certain degree of risk directly linked to probability theory. That is, the less time you spend on such slopes, the higher the probability of passing them safely… This, in general, applies to all types of rockfall.
“The time has come”…
As a rule, this is connected with some large piece of rock or ice — it does not matter which — often lying or standing separately. Something underneath it has been breaking down, cracking, and weakening, and then it finally collapses… In terms of timing, it can happen at any moment. In other words, it is impossible to include it in a movement plan.
Here is just one example. It happened to us on Tyutyu-Dzhailyk Pass, grade 3A — also known as Suvorov Pass — in 1999. I should say that during that season four groups were cleared to attempt this pass, but only we completed it… Yes, it looked genuinely frightening: the entire northern slope was black with rocks of various sizes.
It looked as if rocks were flying there in a continuous stream. We observed for half a day and made reconnaissance sorties. Of course, there was a fair amount of rockfall, but within reasonable limits — meaning that an early start solved the problem of safe passage, and in general, it did solve it. But there was a large slab lying in the big couloir — about 4 meters in diameter and roughly a meter thick. And its time came to move — at 4 a.m., still in the twilight. The sound was indescribable… Visibility was poor… And this thing began rolling down the couloir, then overturned from the edge of the bergschrund straight onto the ice above us. It knocked out about a cubic meter and a half of ice… It felt like a cannon firing buckshot — from small pellets to pieces the size of a head… A moment earlier there had been one separate flying “suitcase,” and quite a slow one at that — and then it turned into a heap of ice fragments flying at high speed in a solid wall.
At first I tried to dodge, as we had been taught, but after getting hit painfully in the face a couple of times, I put my helmet forward. What did it feel like… Like a turtle hiding its head, with the head jerking up and down. In other words, it was being pressed into the shoulders… Then the “shrapnel” flew past, and the culprit of the whole incident appeared, sliding slowly. From above, the guys thought it was heading straight for me and was about to smear me across the slope, so they were all shouting something at me… But I could see that it was going past, 1.5–2 meters away from me. Still, it was a four-meter rock block… It seemed to cover the entire slope. I was more worried about Shurik, the last climber below — he had jumped into the bergschrund and was waiting for this “suitcase” there. We got away with it. Then we continued across the rockfall-prone slope of the pass, and by 8 a.m. the last member of the group had moved onto the fixed ropes on the eastern wall of Tyutyu, while the slope came alive. Here, the rockfalls were mainly the result of rocks melting out of the ice, so it kept pouring down as long as we were able to observe it.
Another example… On Rebro Pass, grade 3A, in the Pamirs. On one side there is a long rocky-scree ridge, the “rib,” along which the group was ascending… The angle was not steep, no ropes were needed. They stopped for a rest beside a large boulder on the scree. One of the participants leaned back against the boulder — and the boulder started rolling… Over the participant.
The “human factor”
Do not go into the mountains and you will never be caught in a rockfall — that is a fact. But if you do go, such encounters are practically impossible to avoid. The other question is that by following certain rules, it is possible to avoid “successful” encounters. The simplest human-caused case is dislodging a rock with a careless movement. As a rule, a rockfall-prone slope is scattered with individual stones or groups of stones, on ledges, flatter sections, and so on. If there is nobody below you, you can — and often should — simply knock down anything loose or badly placed. But when there are partners below, you must act more carefully. For example, move it aside if possible. But avoiding such “dislodgements” completely is practically impossible: you step badly, your foot slips — and that is it, off it goes. Rockfall from another group moving above you is also possible, though nowadays this happens rarely, since the number of groups in the mountains has decreased significantly.
There was a case when two groups were moving across a grassy slope on parallel trails. The upper group accidentally dislodged a rock — weighing several kilograms — and one participant in the lower group was killed. For context: the slope was essentially not considered rockfall-prone, so no observers were posted. Yes, rocks fly quietly through grass and are hard to see if the grass is high enough. So without observers, there is a high probability of not noticing them in time…
And, of course, the rope. If a rockfall-prone section requires rope use, it is also practically impossible to avoid knocking down stones with the rope. It does not matter whether it is a descent or an ascent. And when the rope has to be pulled down during a descent, a lot may “come flying.” But the human factor also has one advantage: the rocks only start accelerating from the level where the participants are located, so their speed is relatively low, especially compared with rocks flying from high above… Taking acceleration due to gravity into account, of course…
In my own practice, there have been quite a few human-caused rockfalls. I will try to describe several examples…
In the 1980s and 1990s — that is, when we were young — we practiced high-speed descents down scree and moraine slopes. There is a certain advantage to this, as it saves energy: you descend in 5–15 minutes where a group usually takes at least half an hour, or even an hour or two. But you must understand that falling with a backpack at that speed can have serious consequences, especially on a moraine or scree slope with large blocks. In other words, you need good coordination that allows you to maintain balance even when stepping on “live” rocks. I could do it… You run, and around you a mass of stones gradually gathers speed and flies downward… When there are too many of them, you make a sharp maneuver 5–10 meters to the side, stop, and let the flying stones pass… Then forward again… Yes, before doing this, think carefully: a broken leg means the guaranteed end of the route, at least for you. And make sure there is nobody below — no other groups, no shepherds, no gatherings of animals.
On the descent down the wall from Diklo W. Pass, grade 3A, in 1984 — led by Lena Titkova — the rope got stuck while pulling it after the third rappel. Climbing back up in that part of the descent was too dangerous. So Sasha Klyuchnik and I started jumping on the pull-down rope, luckily on a fairly wide scree ledge where these “maneuvers” were taking place. On about the tenth jerk, the rope “went” — along with a truckload of rocks. Up to 40–50 cm in size. We barely managed to jump away from them… I have never pulled down such a volume again… If we had not managed to jump aside, there would have been no chance.
Another pass in the Eastern Caucasus — XXVII Party Congress Pass, grade 3A. On the descent along the ridge from the pass, there was a 60–70-degree rappel. There were many ledges, all covered with stones… Not dislodging them was impossible. So we descended diagonally, moving away from the “line of fire.” And each participant sent down their own portion of rocks.
And on the traverse of Garmo Peak in 1992. Yes, we had plenty of adventures then… On the descent, somewhere around the third rappel, Anton “caught” a rock. Yes, he was the last one, and most likely dislodged it with the rope. He was unconscious for about 10–15 minutes. Luckily, the rock struck tangentially. Five to ten centimeters to the side — and there would have been no chance. And in essence, the helmet saved him. The rock split the helmet in half — back then we used construction helmets — injured his head, and hit his collarbone. Yes, we were at the belay station beyond the lip and could not see Anton. I was already about to climb back up when he appeared… Well, the main thing was that he was walking by himself… He was staggering, but he did not lose consciousness again. That is how we got down to the tent, and only there were we able to clean and bandage the wound. There was a lot of blood; the cap was completely soaked. And we only found out at home that his collarbone was broken… Just one rock…
What characterizes a rockfall?
What criteria determine whether it is possible to pass here, or whether it is too dangerous? True, there are situations when you have to pass “regardless of…” because there are no other options. The main factors are:
– volume;
– speed;
– size;
– frequency.
Volume means precisely the amount of rock arriving in a single fall — individual stones, small groups, or “truckloads.”
You can proceed from a simple definition: the more there is, the worse it is — meaning, the more dangerous… Accordingly, you get the required number of “dodges per minute.” And I think it is obvious that once a certain number of stones are flying, dodging is no longer possible — only shelter or covering yourself with a backpack. The greater the volume, the higher the probability of being hit.
The volume can be anything… Think of the Usoi landslide, which buried an entire village and formed Lake Sarez in the Pamirs… That is not exactly a rockfall, but a collapse — a landslide — caused by an earthquake. I observed a similar collapse in China, only it was a pure rockfall. Yes, the sizes of the fragments varied greatly; some were the size of a five-story building. It happened sometime between 2002, when we walked there along a trail by the river, and 2006, when we entered that valley for the second time, at the end of our third expedition. To bypass the newly formed lake, we had to gain height, cross this dam of debris, and then climb down. There was no proper trail yet, only tracks…
Speed depends on the length — that is, the height difference — the steepness, and the character of the slope.
Clearly, the longer and steeper the slope, the more acceleration there is. But it also depends on the nature of the slope. For example, rocks slow down on snow, and in fresh loose snow they lose speed and stop fairly quickly. Large rocks also slow down on scree slopes. On hard firn, they punch holes with their mass and lose speed, often stopping. Or, conversely — especially on steep slopes — a rock collects everything that is poorly seated along its path, and what began as one stone arrives as… something much more. They also ricochet and change direction in flight…
Yes, speed… It can be anything. And it is anything — from slow-moving, like the “suitcase,” the huge rock I described on Tyutyu-Dzhailyk Pass, to shell-like speed, when a flying rock cannot be seen at all… We were descending from Barrier Pass — grade 3B*, first ascent, 1993 — onto the Kaindy Glacier. At the junction of a side tributary with the main body of the glacier there was a substantial icefall. A bypass of the icefall appeared to run along the right edge, so that is where we went. Suddenly there was a whistle and an explosion ahead of us; shards of ice, smashed out by a rock, flew in all directions… Again a whistle — explosion, whistle — explosion, smaller, larger… We were walking along a wall about 600 meters high, and they were coming from there. The good part: there were not many of them, mostly single stones. The bad part: you could not see them — only the sound, the whistle, and then the explosion… Intervals were one or two minutes… In such cases, if it hits you, it kills you — that is obvious. We ran through in rope teams, one at a time: one team ran across the section — yes, ran with backpacks — while the other observed. Not to warn; everyone could hear the whistle. They watched to see whether it hit or missed. Here, probability theory worked in our favor: it missed.
Size means the dimensions of the fragments
They too can be as large as anything. These are mountains… And rocks can also shatter when hitting the slope or one another… There was one — now there are many. Yes, the size of the fragments, combined with speed, determines the possible outcome of an encounter. It may be a bruise, cut, or scratch — with no consequences for the route. Or it may be a serious injury or death — which means guaranteed withdrawal from the route…
Size can also be anything… On the collapsed mountain in China, the largest blocks were the size of a five-story building. In other words, climbing over them was simply impossible, even with a rope. It is hard to imagine what they were like when they broke away. Yes, being caught in such a collapse leaves no chance… I do not know the cause. The area is generally seismically active, or perhaps “the time had come.” It is unlikely that this can be known.
And in the area of Bozhya Korovka Pass — grade 3A–3B, Chinese Tien Shan — we also observed a grand rockfall while descending onto the glacier of the same name in 2004. We crossed this pass, as it were, in two stages: in 2002 from the north, as part of the Bozhya Korovka — Plato pass combination, and in 2004 we completed the southern slope, descending after the traverse of Kashkar Peak, 6435 m. In 2002 we were choosing between two saddles — the lower and the upper — and at the time we chose the upper one… We ended up below the lower saddle in 2004, after descending from the traverse and therefore down the southern slope of Bozhya Korovka Pass.
We had just sat down to rest below that lower saddle. A snow slope of 25–40 degrees rises toward it, then rock outcrops begin. It was already evening, around 20:00; the slope had gone into the shade and was evidently beginning to freeze. Suddenly there was a loud crack, and off it went… A piece of rock of some unbelievable size broke away and flew toward us, breaking into pieces along the way, also far from small… It was clear that it would not reach us: after eight days of bad weather there was about a meter and a half of fresh snow on the slope, and the rocks were slowing quickly.
And still… The instinct of self-preservation stirred somewhere inside, warning us: the size of the flying rocks was very impressive… Another crack and roar — and the next unbelievably large portion broke away from the massif and collapsed. There was not enough room; multi-ton blocks collided in the air, and some of them bounced in an arcing trajectory toward us. One entered the snow about a meter from one of the participants and disappeared. I think it went deep — the kinetic energy was enormous. It became clear that we needed to retreat farther away from such fire. Grab the packs and run — and, considering our acclimatization, exhaustion, and that persistent inner voice, we were running quite briskly. We heard and watched the next crack and roar as grateful spectators — grateful because we had once again been let go without consequences.
Frequency
This is intensity — that is, how often the “shelling” repeats: at short or long intervals, or as a continuous stream.
I remember the description of the southwest face of Peak Communism in A.G. Ovchinnikov’s book “Climbers of the Bauman Moscow Higher Technical School.” In the lower part of the route, things were flying continuously, both day and night. At night only slightly less often and slightly less… But they had to climb — that is, they wanted to, since it was for the Soviet Championship after all. The decision: climb at night, because you cannot see anything, which means you do not need an observer and you do not need to dodge… Everything is solved through speed, that is, probability theory: the faster you move, the higher the probability of slipping through safely. By morning they had passed the main “garbage collector”… But not all of it. For an understanding and an “inside” feeling of that ascent — and, I suppose, of all other ascents on that face — I recommend reading Volodya Stetsenko’s account of climbing the South Face of Peak Communism.
So, two causes remain: freezing/thawing of rock — of water — and rocks melting out of an icy or firn slope. Both of these causes have a rhythm. This rhythm can and should be used when choosing a tactic for passage.
Thawing/freezing of rock terrain is, of course, connected with the presence of water on the rocks — snow or ice higher on the slopes, in cracks and fissures.
Basically, it happens like this: the slope goes into the shade or night falls, the temperature drops, and the water on the terrain begins to freeze. And let us remember physics: it expands and begins tearing apart the surrounding terrain. And it falls if it is in an unstable position or on a steep slope. These may be small fragments, or they may be simply enormous. But not everything that breaks off falls immediately — some of it freezes in place and thaws out only in the morning or during the day, as the temperature rises. All of this flies in the morning hours. I do not give exact time frames; it is impossible. Much depends on aspect, altitude, season, and weather. But at night and in the morning hours, as a rule, there is a “safety window.” If you can pass the rockfall-prone section — or the most rockfall-prone part — during that time, go ahead. If not, it is better to use the daytime period after the morning rockfalls subside and before evening. If you still cannot make it… Then read about the southwest face of Peak Communism, where it was pouring down around the clock. In other words, dodge whenever possible and make maximum use of natural shelters…
Melting of glaciers heavily contaminated with rocks
Here the timing pattern is somewhat different… As soon as the slope is illuminated by the sun, it begins… And it continues until sunset or until the slope goes into shade — and again, everything depends on aspect, altitude, season, and weather. But in general: illuminated and warmed up — everything starts flying; it goes into shade and cools down — everything stops… And again, everything depends on volume. Here too, it is probability theory… In other words, the more that is flying, the higher the probability of an encounter… The greater the speed, the higher the probability… And do not forget: these are mountains… In the first case, the rocks are being torn apart — and early morning and daytime are available for movement. And most of the night as well… But rocks melting out of ice or snow can be passed safely only at night or early in the morning. Or you dodge… Or use shelters…
Yes, about shelters… It is far from always possible to pass a rockfall-prone slope in a single day, let alone within the time windows described above. This does not mean you have to retreat. During the available working time, you need to move as far as a safe shelter: get under an overhang, climb into a crevasse, move aside onto a ridge or a ledge over which everything flies, and so on. Everything is possible.
So where is the line that can be used to give an unambiguous assessment of whether it is possible to pass here or there? There is no such line. Everyone has their own evaluation criteria. That is why I mentioned the southwest face of Peak Communism. Considering the number of teams that climbed there, it can be said that for most active athletes it is impassable. Or the degree of risk exceeds reasonable limits — for most… But there are those who will say: we want to… And undoubtedly, if there is time and opportunity, one must observe, especially if it is a first ascent and the behavior of this particular slope is unknown. It is best to observe for at least half a day, and better for a full day, two, or three… Then there is a chance to take everything into account: altitude, aspect, frequency, and volume. Of course, keeping in mind that you still will not know everything… Or you go straight in, using whatever information may be available about similar slopes in the area. Going by analogy. It works quite well.
And yes, do not forget: these are mountains… In other words, a big “sandwich” of every kind of terrain. Therefore, the presence of shattering rocks does not at all exclude the presence of melting glaciers, and vice versa. I would even say that most often all rockfall variants exist simultaneously. So if you want to go, observe and think. And once you decide to go, choose your option and do everything as quickly as possible. Only then is there a high probability of success.
EXAMPLES:
Conglomerate glacier
The upper reaches of the Khargabe River in the Eastern Caucasus, in the area of Diklo Peak — the highest summit of Dagestan. The year was 1989, a fifth-category mountain route consisting entirely of first ascents. In the upper reaches of the river, we crossed three new passes: Khargablam 2B, Shiroky 2B, and Japaridze 3A, and for dessert we traversed Diklo Peak. And we could not understand why, despite excellent weather, a small cloud constantly hung in the cirque of Japaridze Pass. Given the increased rockfall danger in the area — we ran, dodged, hid, and moved at night — we headed for the pass in the dark, climbed onto the icefall, and crossed it from west to east. The entire icefall was covered with rocks, and the ice was black. We crossed it in the dark and moved farther east onto a relatively clean snow slope. At 6:00 a.m. the sun lit up the ridge of the Snow Range — and it began… It was flying almost continuously, and the little cloud appeared immediately: it turned out to be rock dust… The size ranged from small debris to “suitcases” as big as a wardrobe. It was impressive to watch the larger rocks cut down seracs like a huge razor. Somewhere up there was what we called a “conglomerate glacier,” and it kept shedding and shedding… Until evening. Then silence — until morning.
There, on the traverse of Diklo Peak…
The exit onto the ridge of the southern summit involved 280 meters of ice. It was “shooting” — rocks melting out — along the right, upper edge of the glacier, that is, from the side. It was shooting in a fan and in large quantities, but mostly small pieces, while the bigger ones, about the size of a plate, perhaps numbered a dozen in each batch. In terms of timing, it was lunchtime, the hottest part of the day, meaning we were going at exactly the wrong time. But every one or two rope lengths there were shelters: rock outcrops with a hollow-randkluft where the entire group could easily get in. Using these shelters, we passed, generally without incident.
Barrier Pass 3B*, first ascent, 1993.
While ascending from the Shokalsky Glacier, we planned to go directly up the rock bastions — four rock bastions in total. Since it was clear that the ascent would take far more than one day, we set out in the dark, around 4 a.m. On the approaches to the first bastion, a snow-and-rock couloir opened behind it — a garbage collector through which the first bastion could be bypassed, and that is what we did. By 10 a.m. we reached the “top” of the first bastion — a good bivouac spot, and we really should have spent the night there. The weather was overcast and it was snowing, so based on our knowledge of the area, we decided that we still had a couple of hours in reserve and rushed to bypass the second bastion. In the couloir there was a large rock plug; the rope led upward on the left in the direction of travel over ice, then a traverse mostly over ice to the floor of the couloir, and then another half-rope length into a side couloir — that is, away from the garbage collector.
The awareness of time pressure forced us to violate the traditional rules, because we had to get out of the main garbage collector quickly. So as soon as the fixed rope was anchored, everyone started moving at the same time. Yes. When everything ends well, it is even pleasant to watch. Exactly at 12:00 we pulled the last rope out of the couloir — and it started, as if someone had pulled the toilet handle. A roar, and a huge mass of rock, ice, and snow thundered down the couloir. From above we could see the “garbage” rolling out onto the Shokalsky Glacier, erasing all traces of our presence… If something had happened after that, they would not even have known where to look for us.
The wall of Shokalsky Peak is large, and we were not climbing to the lowest point of the saddle at all… During five days of ascent, we studied the rhythm of the couloir thoroughly. In good weather it began “working” exactly at 10 a.m. In overcast weather, from 12:00–13:00. And at intervals of 30–60 minutes, something constantly flew down it. Past us. And another thing: as a rule, a couloir is the easiest line of movement up a slope or wall. In other words, your feet want to go there. But as a rule, it is also the main garbage collector. So you can go there, but only at the right time.
Chonteren Glacier, eastern branch.
The route was unknown, so we were doing reconnaissance. At a bend in the glacier there were crevasse systems, some kind of couloir with a stream, and something was regularly flying out of it. I told the guys to stop and went to look for a bypass over moderately difficult rock. Without a rope it was unpleasant, but climbable. I reached a ledge; beyond it was a large, convenient pocket for ascent. Great. I prepared an anchor, hung the rope, came out — and they were already moving, straight into the icy couloir… I shouted — useless, the noise of the water and the regularly sliding rocks drowned everything out.
This is how it looked to me: a slab comes flying from above, about one meter by half a meter, 20–30 centimeters thick, hits a participant in the back at waist level, he lands on the glacier — that is it. From such a blow… But then I see him move, get up, and walk by himself… Incredible. When we gathered on the ledge, everything became clear. The slab had hit the lower part of the backpack, throwing the participant almost into a horizontal position, and the slab passed underneath him at quite a speed. He simply fell onto the glacier from a height of about a meter. He got away with only slightly scratched palms from landing on the ice.
Of course, this is not a training manual. Rather, it is a reminder not to forget about tactics. Because I read reports from recent years: “we started very early, at 8 a.m…”. That is not early. That is catastrophically late.
I have never had to abandon a route because of increased rockfall danger. We always found a solution. Even that year on Tyutyu-Dzhailyk Pass, which only we completed that summer — although four groups had applied. Everything there was black with rocks. But with Tugbelchi Pass 3B* in China, we did have to make a decision in 2002. True, not because of rocks. The pass is two-sided, and I would rate each side as 3B. On one side, from the north, there is an icefall — or rather, an ICEFALL. On the other side — well, I have described that more than once. So, if I had seen such an icefall 10–15 years earlier, that is, in the 1990s, I would not even have paid attention to it: impossible to pass. Moreover, if I had seen the whole thing in 2002, I might not have gone into it. But we did pass it. Although calling it passable is something I cannot bring myself to do. So it is with you… It is possible that today there are simply no athletes capable of or willing to climb the southwest face of Peak Communism. Perhaps there never will be again. And do not forget that you can find another adventure that horrifies your “inner voice.” Somewhere nobody has been before. For example, the south face of Pobeda Peak. That is one I know about. Quite a problem. Completely autonomous, unlike most high-altitude expeditions. But there are also many unclimbed routes in the big mountains.
Author: Anatoly Dzhuliy
Article source: alp.org.ua