In saying that this sort of weather was harmless, I am not denying that it hindered our operations; but from the point of view merely of the climber it was remarkably innocuous. A case in point is our ascent of Ri-ring. As we were nearing the summit a thunderstorm gathered to the North and dark clouds came up on every hand, threatening a violent disturbance. I have related in an earlier chapter how we hurried down, expecting at the least a cold unpleasant wind and some nasty snow showers; but the air remained calm and the temperature warm and such grains of snow as fell were hardly remarked in our flight. A more disagreeable experience was our first journey to the col from which we afterwards looked into the West Cwm of Everest; we reached the pass in the teeth of a wind which drove the snow into our faces; but the weather had no real sting, and the wind, though cold, seemed to touch us lightly. Wind, in fact, was never an enemy to be feared during the whole period of the monsoon, and snowstorms, though they prevented more than one expedition, never turned us back. The delays in our reconnaissance caused by bad weather were of course considerable; we were forced to push our camps higher than would have otherwise been necessary, and often found ourselves hurrying after a start before dawn in a desperate race with the clouds to reach a view-point before the view had disappeared. And the precipitation of snow on the glaciers forced us invariably to wear snow-shoes on névé, and consequently limited the numbers in our parties.
I have already alluded to a more serious snowfall which took place from July 20 to 25. Another occurred during the first days of August and another again on August 20 and 21, when snow came down below 16,000 feet. In September, towards the end of the monsoon, the weather was more monotonously malicious and the snowfall tended to be heavier; I find two heavy falls noted particularly in my diary. But on the whole it was the habit of snow to fall lightly. It is remarkable, when one calls to mind such a big snowfall as may occur during the climbing season in the Alps before the weather is resolved to be fine, how little snow by comparison fell on any one day in the region of Mount Everest. And perhaps in the end the slopes were more laden by the smaller precipitations which deposited a daily accretion.
We naturally sought an answer to the interminable query as to how much melting took place at the highest altitudes. Melting of course was always quicker on rocks. But even on the glaciers it was remarkably rapid whenever the sun shone brightly, and we were more than once surprised after a period of cloudy weather with constant snow showers to find how much the snow had consolidated. It seemed to us on more than one occasion that while snow had been falling at our camps and on the lower peaks, Everest itself must have escaped. But, generally speaking, after July 6 the mountain was remarkably white and became increasingly whiter, and only at the least two perfectly fine days, which rarely came together, made any perceptible difference. It was remarkable how little ice was ever observable on the steep Eastern face, where one would expect to see icicles hanging about the rocks. It is my own impression for what it is worth, and its value I fear is small, that though snow will melt readily enough low down, at least up to 23,000 feet during the warmer weather even on cloudy days, at greater altitudes, perhaps above 25,000 feet, it rarely melts even in bright sunshine. In September this year I doubt if it melted at all above 23,000 feet after the weather cleared. At lower elevations the direction and angle of the slope made all the difference. After one fine day the snow on a steep East slope had solidified to a remarkable degree at about 20,000 feet; on a North-facing slope at a similar elevation it had been quite unaffected; on flat surfaces 1,000 feet higher a perceptible crust had formed, but the snow remained powdery below it as on the day when it fell. After three and four fine days the snowy surface of a glacier was absolutely hard at about 20,000 feet and remained solid in the afternoon. Fifteen hundred feet higher we were breaking a hard crust and sinking in a foot or more. This condition may have been partly due to the local behaviour of clouds, which were apt to cling about a ridge overlooking the glacier and cast a shadow on this part of it. But higher, on more open ground, we met the same condition; and again the slopes facing North preserved a powdery snow which never changed before it was blown down in avalanches. Perhaps the most convincing phenomena were the powdery snow high up on the Eastern slopes under the North col and the snow on the Western slopes at a similar elevation under Lhakpa La, which was hardly more solid, while 1,000 feet lower we found excellent snow. It is difficult to resist the conclusion that altitude is a determining factor in the sun's power of melting. It is possible that a line might always be drawn on any given day above which the temperature of the air is too cold for snow to melt where it has fallen on snow, and another to meet the case where it covers rocks. From our all too limited observations in June I should judge that in the middle of summer such imaginary lines would be above the height of Everest, but in other and cooler seasons we should quickly find them lower and a long way below the summit.
In close connection with the snow's melting we had to consider the possibility of avalanches. Our observations on this head were so meagre that I can only make with the greatest diffidence a few statements about them. It is astonishing to reflect how seldom we either saw or heard an avalanche, or even noticed the débris of one under steep slopes which had been laden with snow. Only on two occasions, I believe, were we confronted in practice with the question as to whether a slope could safely be crossed. The first was on August 7 in ascending the peak Carpo-ri, of which I have previously made mention. The heavy snowfall at the beginning of the month had ceased during the night August 4–5; the following days had been warm but cloudy, and on both there had been prolonged snow showers of the lighter sort in the afternoon and evening. On the night of August 6 we had hard frost at 17,500 feet, and there was a considerable sprinkling of fresh snow on the stones of the moraine. Between the col and the summit we met some very steep snow slopes on the South side: we carried no clinometer and I shall not venture to estimate their angles of inclination. It was on this occasion, as I have narrated, that in crossing a shallow scoop I was very much afraid of an avalanche, but was able to choose a safe line where we were protected and helped by an island of rocks. The snow here was inclined to be powdery; but it had solidified in some degree and, where we had to tread it, adhered sufficiently to the slope so as to give one a distinct confidence that it would not slide off wherever it might be crossed. Above this place we were able to avoid danger by following an edge where the snow was not so deep; but here again I noticed with surprise the adhesion between new snow and old. The ice below was not solid and smooth, but frothy and rough, and easily penetrated by a strong blow of the axe; it seemed to have been formed very quickly. The snow showed no inclination to slide off, though it was not of the substance in which a secure step could be made: and I concluded that the process of assimilation between the old surface and the new snow must proceed very rapidly whenever the temperature was warm enough. On the final slope, which was even steeper, more snow was lying—it was a more powdery substance: I was able again to escape danger on an edge dividing two faces; but it was surprising that no avalanche had already taken place and that the snow contrived to stay where it was.
The other occasion when we had to face and determine the possibility of an avalanche was in traversing the slopes to the North Col. Here our feet undoubtedly found a solid bed to tread upon, but the substance above it was dubiously loose. It was my conviction at the time that with axes well driven in above us we were perfectly safe here. But on the way down we observed a space of 5 yards or so where the surface snow had slid away below our tracks. The disquieting thoughts that necessarily followed this discovery left and still leave me in some doubt as to how great a risk, if any, we were actually taking. But it is natural to suppose that at a higher elevation or in a cooler season, because the snow adheres less rapidly to the slopes on which it lies, an avalanche of new snow is more likely to occur.
Temperature
Before attempting to draw conclusions as to the relative chances of finding favourable conditions between one month and another, a few words must be said about temperature.
So far as the temperature of the air was concerned, we experienced no severe cold and suffered no hardships from first to last. I do not mean to affirm that it was always warm. We welcomed frost at nights as one does in the Alps. One night so early as July 18, in a camp above 19,000 feet, was exceptionally cold. At our two last camps in September the thermometer went down to two or three degrees below zero (Fahr.) and the wind at the final camp made it more difficult to keep warm; with as little protection as the coolies had, I should no doubt have shivered in my tent. The air also seemed very cold before sunrise on September 20, though we were walking fast; but it did not bite the tip of my nose or ears or cause any disagreeable result. In general it may be said that there could be no difficulty in providing equipment against any cold we encountered. Heat was a much more dangerous enemy, as I indicated in describing our first ascent to Lhakpa La. Personally I never felt the sun's power on my head, but I felt it on my back so early as 8 a.m. as a definite attack on my energy and vital power, and more than once, though the sun was not shining, in crossing a glacier late in the day I was reduced from a state of alert activity to one of heavy lassitude.
The temperature of the snow is another consideration of very great importance. Even in July I felt the snow to be cold in the middle of the day towards the summit of Ri-ring, and when wearing snow-shoes in fresh snow under 20,000 feet coolies and all felt the cold in their feet. Later I apprehended a real danger from this source. The coolies were encouraged to anoint their feet with whale oil, and we avoided accident and even complaint: but I always admired their resistance to cold. Personally, though I am not particularly a cold-footed person, I took the precaution of wearing two pairs of long socks which were both new and thick, and a third from which, unfortunately, the toes had to be amputated owing to the timid miscalculation of my bootmaker: this equipment sufficed and I found my feet perfectly warm, while one of my companions was obliged to pull off a boot in order to restore circulation, and the other went on with numb feet and barely escaped frost-bite. And I must again emphasise the fact that this was on an Eastern slope well warmed by the sun in the middle of the morning and at an altitude no higher than about 22,500 feet. It may readily be concluded that forethought and care are in no respect more necessary than in guarding against frozen feet among a large party at the highest altitudes. And the difficulty of guarding against this danger might well determine the limits at either end of the warmest weather within which an assault should be launched on Everest itself or any one of the half-dozen or so highest peaks.
The Best Season for Climbing