WEATHER
There is one variable which belongs to the mountaineering rather than to the human division of the problems with which management has to deal. The weather is the background, foreground and middle distance of all big mountaineering. A change can upset the nicest adjustment of a climb to the strength of a party or to the length of a day. Every climber keeps one eye on this irresponsible neutral, which may at any time turn the scale of the campaign against him.
As a result, no mountaineer will endure, and no leader can afford, not to be thought a good weather prophet, even though the reputation be confined to his own mind. In reality, so unaccountable are changes in the hills, any fame acquired for infallibility must be the result of a large share of good fortune. The happy confidence in his own forecasts, that every leader owes it to his party to display, can only be based upon a few broad considerations, and upon bluff. No previous appearance of a mountain sky can be taken as sure ground for certain prophecy. A particular wind or ‘sign’ may mean totally different weather in two adjacent valleys; or the whole doctrine of the winds may be unaccountably reversed in an exceptional season. In the Alps, for instance, a north wind usually means clear, brisk, settled weather; a west wind, the continuance of unsettled weather; a south wind, a succession of storms that come and pass. But the seasons from 1909 to 1912 will provide instances of the north wind blowing continuously through alternate days of excessive and moderating rain and snow, and of the south and west winds attending an unbroken season of hot sunshine.
A leader, therefore, besides his groundwork of elementary knowledge, has to make himself acquainted with local signs of wind and weather in every season and in any new district; with such details, for instance, as that in the Zermatt valley “the weather comes from the west,” or that in Courmayeur we watch the south and west and do not bother with anything north of the range. Further, that in the Oberland a north-west wind brings storm, but a north-east wind brings clearing weather; that bad weather follows closely on a wind blowing over Col Theodule and round the west of the Matterhorn, but that a wind over Col du Lion and round the Matterhorn to the east is a fair-weather sign. He has to discover the relation which the prevailing wind bears to the weather conditions of a particular season or month. The one thing he can count upon is the habit that weather establishes in the Alps during two summers out of three of remaining one thing or the other for a continued period, once it has started, and of returning to this ‘habit of the season’ whenever there are not evident signs that it means to recommence or continue a spell of change.
The scientific study of weather, and its prediction by the barometer and thermometer, are matters for a whole book, and the authoritative textbooks are available. Instruments larger than of pocket size are something of an encumbrance to a climbing party, although I have always made an exception in favour of the pocket aneroid, because of the excellent humour with which it blesses its possessor whenever its statements and those of the atmosphere or the map happen to coincide. I limit myself here to recalling briefly some of the visible, ordinary and less esoteric ‘signs’ which have proved of common use in my own experience, more especially in the Alps.
Clouds.
Clouds form our principal sign. It is important to remember that clouds, while they continue to retain their original form, whatever that may be, will inflict no rain on us. It is their changes, when they alter, that we watch, and we predict rain or not according to their character during and after the changes.
We distinguish between the upper strata of clouds, whose character and direction are important as giving us the eventual direction of the wind and the more permanent character of the weather, and the lower strata, which have only a meaning for the day or hour, and are not prophetic.
In general, clouds in the east alone are a fair sign; clouds in the west, especially dark clouds, mean rain soon.
High-travelling cirrus clouds portend rain. In the Alps, where the winds are our real prophets, a distinction is introduced: cirrus, high and fast on a south or south-west wind, has its usual meaning; but cirrus on a north, east or south-east wind may accompany or, more rarely, precede good weather. Castellated cirrus is always a bad sign, and, where the horizon can be seen, the appearance of cirrus in bands lengthening up towards the zenith (cirro-stratus) is an unwelcome event. Dappled cirrus, the so-called ‘roses’ of the south and the ‘sheep flocks’ of the north, implies a change of wind and weather. As the presence of high cirrus, upon which the change of wind can produce the dappling, usually means, in the mountains, that uncertain or bad weather has been preceding the change, the dappling is most often, and with justice, taken as a good sign. If, however, the weather has been dull, with merely clouds of heat, and the wind has been good before, the change portended will be probably for the worse.
Cumulus clouds, when they tower rapidly, and more especially when they ‘topple over,’ or show a tendency to do so, are signals of a change to rain. A sure method of observing cumulus is to watch some small portion of the cloud for a space of time. If it grows larger, the sign is a change for worse weather; if it ravels out and disappears on the warm air round it, the sign is for good, and the cloud can be disregarded.
Stratus, the long stratified bands of cloud at any height, means bad weather, and the tendency of cirrus or cumulus to stratify is ominous.
The edges of clouds tell us much of their import: harmless if they are filmy and ravel out on the warmer air; suspicious if they are hard, heavily outlined or charged.
An approaching rain-cloud in action is recognizable by the vertical or slanting lines in the air below it, or by the ‘torn lace’ on the lower edge. A hail-cloud shows heavier lines. A snow-cloud carries fuller, harder marginal protuberances, and may be lighter in tone. Heavy cumulus of this cumbrous sort may often surprise strong sunlight by a sudden snow-break. Usually we go by temperature and height in predicting if a ‘wet’ cloud will break in rain or snow.
High ‘mare’s-tails’ betray wind, and predict rain according to their direction.
‘Fish’ clouds pointing east and west usually mean foul weather; pointing north and south, fair weather.
Black wisps of cloud before sunrise, especially in a clear sky, mean early rain. Lighter-toned wisps at this hour have no signification. But if the lower edges of cloud-films are charged and dark, looking like ink which has run down into the borders of blotting-paper, we look out for rain.
Long fingers of cloud radiating from a peak portend storm, particularly if any one of them betrays the typical thunder-curve. Thunder on a peak means snow, so we must look out for a cold and electric day.
Thunder-clouds are easily distinguishable. Their form is always similar. The duplicated outline in the masses of cloud above and below, the connecting darker neck between, and the leaf-like and invariable curve of strength where the neck runs out into the profile line of the upper mass, are sufficiently distinctive. A little further observation will enable their lines of system and the probable direction of their movement to be located. The lower mass of cloud may, in cases, be absent, but the truncated ‘neck’ and the leaf-like ‘curve’ will always enable us to identify them.
Wind.
Even more than the clouds, once we have discovered the habit of the year and the local signs, the winds are our firm basis for forecast. The north wind in the Alps is usually for good, though in a bad season of habit it may, if long continued, bring snow. The south wind is always fraught with suspicion, until it justifies it. It brings a succession of storms, but leaves fine intervals. The west wind, if continuous, means the continuance of unsettled weather, with an inclination to preserve whatever may be the habit of the year. It is perhaps the most forcible and trying of winds to encounter on the ridges exposed to it. The east wind is infrequent and rarely long continued. Its portent is favourable. The south-west wind means rain to follow. A change from north to north-west threatens rain. A change from south-west to north-west—generally a wind on its way to becoming a north wind—means a change for the better in bad seasons. South-east, and especially north-east, winds share the good qualities and projects of the east wind.
The current of the Föhn is recognizable by its accompanying oppression of warm-parched, or in cases of warm-moist, atmosphere, and by its depressing effect upon our spirits. It is a harbinger of evil of all kinds. Its own forerunners are often a massing of heavy-bordered clouds accompanied by a threatening vividness in all visible coloration. The Föhn is said to be able to infect, or more probably alternate with, any wind from any quarter; but we know of it in summer usually in the south or south-west winds. In the south it is ‘dry,’ in the south-west it is ‘wet,’ Föhn. Its presence ruins the best-directioned wind; it underthaws the snow dangerously and spoils our tempers inexplicably.
Sudden gusts and round-the-compass winds are of ill omen. As between cross-currents of wind, at different levels, the higher alone is worth attention. Valley currents, particularly those off glaciers, are only misleading.
The simple sky signs, familiar not only in mountains, give us further assistance.
Signs in General.
A red sunrise is bad; a red sunset good. Sunrise on a grey sky means a fair day; sunset on a grey or pale yellow sky means a rainy day, on a bright yellow sky a windy day.
A ‘high dawn,’ the sun showing first over a vapour belt, is an ill sign; a ‘low dawn,’ the sun leaping from the horizon, a good sign.
If the distant sky at dawn, especially to the west, is low and dark, there will be breaking weather by noon.
A dark blue sky tells of wind, and probably rain to follow; a light blue sky is of fair weather.
All over bright or gaudy colours at sunrise or sunset, and all hard outlines, foretell rain and wind. Delicate colours, well-blended tones and filmy cloud edges are fine-weather prophets.
Rings round the sun or moon, and vivid twinkling stars in the later night, are bad signs. Clear nights of cold, and calm and quiet stars before dawn, are good.
Heavy dews and the falling of the wind at sunset are good signs.
The clearness and nearness of distant hills, except just after rain, is a bad sign; but here we may distinguish between a clear landscape when we face towards the sun, which is an ill sign, and a clear landscape as we stand with our back to the sun, which is quite usually a fair sign.
Ascending mists on hillsides are bad. Mists in valleys at evening, clouds lifting at sunset, and hilltops smoking their pipe of evening peace, are good.
Warm airs as we pass up the lower alps or through the pinewoods mean us well; but warm nights on the height and in the hut, or the sickly puffs of warm breath that meet us from the large crevasses as we start up the glacier before dawn, are omens of ill weather.
Early rain, ‘rain before seven,’ has no serious meaning; it rarely lasts.
Early white mists should never frighten us from starting, but we must judge them by feel, texture and direction of movement. An early ominous mist has a different quality, and lies differently from a simple mist of the hour.
During the day feeling or instinct is still our principal guide as to the durable character of changes or of threats of changes. More especially we go by the feeling of the wind. With a good wind, local clouds may be disregarded. The eye learns to distinguish between the heavy leaden-edged look of an increasing mist, and the peculiar silvery wet aspect, markedly round its edges, of a mist that is in process of absorption in warm atmosphere.
One of the most beautiful, and baleful, warnings in the Alps is the view out and across a golden sea of clouds washing up out of Italy or from the south. They often signify the Föhn. So long as the wind blows off the mountains, they will be kept below for the day; but once they begin to make breaches in the walls and surge over the battlements, a bad afternoon or morrow is in prospect. The change from their golden, fairy-like distant greeting to their wet, cold and gloomy embrace makes us reluctant to recall that they are really the same clouds we admired those hours before.
On large peaks there may be severe local storms even while the sky in general remains undisturbed. Rock peaks, for example the Matterhorn, are conspicuous offenders. A small blister of dark, steady cloud may imply a raging storm on the face below it. Not only at the moment, but as it affects the later condition of the mountain, the occurrence of these storms has to be reckoned with.
From a spell of covered or of broken weather we look for a clearing snowfall as our deliverance; and the more confidently if the wind has continued throughout to blow from a good quarter, north or east. If the fall is followed by clear days and three cold nights, we shall find our high ridges in perfect condition again. If the weather continues broken and therefore warmer, the snow will at least not have made things worse; it will have thawed rapidly. It is also worth remembering that in warmer, broken weather what has fallen as snow at one level may have been only rain at another, even at a higher, and the moment the clouds clear we shall, be able to profit by the calculation. I have known the same storm to have fallen as rain in the valley, snow on the slopes, and rain again on the high ridges.
Habit of the Season.
The habit of the season is always the first matter of study on returning to the hills. In a habitually fine season, it is safe to go up to a hut even on a bad day, on the fair chance of a fine recovery on the morrow. For the same reason, in a habitually bad season, it is too late to wait for the fine day, and then go up to the hut or out to the camp. A leader who braves the ridicule of the hotel and the gloom of the glass, and takes his party up to the hut, with hope undiminished by failure, on bad days in uncertain seasons, will catch each short break as it comes, and get a record of climbs that will shock his valley advisers. He must base his choice, as between the bad days, upon his observation of the habit that is governing the vagaries of the season. A very common feature, in unfavourable alpine months, is the alternations of possible and impossible weather occurring almost every day—a wet day, followed by a fine morning; a breaking afternoon, and again a wet day. It is thus most important to “get the alternate right,” and to correct the order of his going, if to ascend to the hut on each first fine day proves disappointing. In a recent so-called ‘bad’ season a party ascended thirteen peaks in three weeks, by getting their ‘alternates’ right at the start, while most parties got only four or five expeditions in the same time. Occasionally the alternate is one fine day, or fine half-day, in every three. To meet this habit, or to discover the order of the alternates in the first place, it is sound to take up two full days’ provisions to the hut, and to wait there for a day, if the first day fails to change. A fine morning will suffice for most climbs suitable for uncertain weather, and a party who have had courage, and faced the mist, and enjoyed the empty hut at night and a long fair morning’s climb, will often be granted the extra pleasure of meeting the usual crowd swarming up to the hut in the afternoon, attended by every sign of the regular return of clouds and rain.
Persistence.
The real principle is to keep on trying in unchancy seasons, and back up the effort by whatever weather instinct or opportunity of observation we may enjoy. In valleys continuously cloud-covered observation becomes uncertain; often the weather may be already clear at higher levels while it lurks in mist in the valleys. Instinct as much as judgment must then tell us if we may chance a start, on the probability that the cloud is really thin and the summits in sun. An attempt is always worth while if the party is getting depressed by a succession of days of idle cloud in the hotel. Chance often helps our predictions. The occasions when instinct or a momentary sight of the higher and important clouds has given the impulse, added to the occasions when a bold face has been assumed, in spite of a low blanket of mist round the hut or hotel, and a start has been ordered on the chance at the best of clear weather above and at the worst of a bracing tramp up and back, all taken together have made many a lasting reputation for miraculous weather wisdom. Some of the most enduring mountain memories are of days thus retrieved from weeks of ill weather, and spent upon sunny peaks projecting, with only a few isolated and lofty companions, from the seas of cloud that covered all the valleys and lower heights, and with them most of our less fortunate fellows.
Until we possess local weather knowledge, and have rather more to go upon than bluff, a climb should never be actually started in threatening weather, still less persisted in against bad weather; which is a different thing from insisting upon going up to the hut or to the base of the peak on the chance of a change.
Snow, and continued rain, which may mean snow at higher levels, must be accepted as definite bars to starting at all.
Cloud, however, is less justifiably used as an excuse for delay in leaving a warm hut on a dull morning. The personal bias in prediction must be allowed for before dawn. Guides, who are too often treated as infallible prophets, are as susceptible as amateurs, at this hour especially, to specious promptings from the spirit of comfortable inaction. They are apt to delay a start hour after hour, in a hut or camp, for the mist-bank to clear and the day to show its hand; and this with entire unreason. If the weather is going to clear at all, it will do so at the earlier hour at higher levels; and it is common sense not to lose valuable time. The sooner we go up the sooner shall we meet the sun, or find out that it is not there for the day.
Even a stay in a hut is more tolerable than confinement in an hotel. For this reason, and to save the time and patience spent upon going up and down from the hut, as well as to be on the spot to catch the right day, it is often pleasanter to stay up at the hut, and send down a porter each day for provisions. We are then ready when the change comes in uncertain seasons.
Snowfall, however, with its hopeless prospect and unpleasing chilly presence, will suffice to send us down without question. Continued snow will send us yet further; unless we can arm ourselves with the short summer ski. In that case we may still refuse to admit defeat, and mint golden days out of the ashes of a heartless season.
I am speaking here only of weather in the Alps. In more distant and less hospitable ranges, where the base camp and the rescue of civilization are more remote, the same persistent course cannot be maintained in face of continued bad or changeable weather. In small climbing, as in Britain, we need not regard weather at all. It enforces all the observation it deserves by the definite limits which wet or snowy rocks put upon the degree of difficulty which it is safe or comfortable for us to attempt, and by the temporary discomforts and restrictions that wind or snow inflict upon our daily expeditions.