Cirrus

“ Near the high pressure the sky is blue, then as we approach the low pressure feathery cirrus, or some form of windy sky, makes its appearance, while a blustery wind whirls the dust, or blows the soot down; and animals turn their tails to the wind to avoid its force on their faces:
When chimneys smoke and soot falls, bad weather is at hand. The whistling of the wind heard within doors denotes rain. ”

“ When fine threads of cirrus appear as if swept back at one end by a breeze prevailing in the regions in which they lie, the wind on the earth's surface may be expected to veer round to that point if then at some other point. ”

“ The day may close lurid with the frayed streamers of lofty cirrus clouds streaking across the sky—the vaporous overflow of a coming storm—or a week of the same bright weather may continue with the wind all the while blowing softly out of the south, but sooner or later the inevitable winter storm must close this foretaste of the spring. ”

“ The loftiest variety of cirrus appears in the afternoon in very hot weather, sometimes quite late in the evening; and in autumn it is by no means a rare event for it to suddenly form just when the sunset colours are fading, or even after they have paled into twilight. Under such circumstances it stands out of a shining silvery grey colour against the background of the darkening sky. A specimen of it is shown in Plate 5, which shows its extreme slightness of form and delicacy of texture. ”

“ Again, the true high cirri never cross a mountain in Europe. How often have I hoped to see an Alp rising through and above their level-laid and rippled fields! but those white harvest-fields are heaven’s own. And, finally, even the low, level, cirrus (used so largely in Martin’s pictures) rarely crosses a mountain. ”

“ The general idea of the classification is by the heights of clouds, the Cirrus group being the highest, from about six to ten miles, the Alto group, ranging from two to six miles, and the Cumulus and Stratus groups below that. Here," he continued, picking out a photograph that showed only a few faint specks of white, "is a true Cirrus. It is the highest of the clouds, and, as you can see from the photograph, it is delicate [Pg 152] and fibrous. ”

“ On examining minutely the higher regions of the air, especially after the sky has been clear for some time, the spectator will probably see the cirrus descending from above in the form of threads or locks and feathers, which go on increasing until they fill the sky. ”

“ They are delicate, always white, more or less fibrous, and form in the upper part of the trade or the adjoining atmosphere above it. Their character and elevation should be studied, and the observer should be careful to distinguish which is the most elevated. Not unfrequently it may seem, to a hasty observer, that the cirrus is below the cirro-stratus or forming stratus. But the genuine cirrus never is. It forms near, and above, the point of congelation, and is often composed of crystals of ice or snow. If they fall, they melt and evaporate, when there is no storm, before reaching the earth. ”

“ Cirro-nebula, or Cirrus haze. Cirrus excelsus, or High cirrus. Cirrus ventosus, or Windy cirrus. Cirro-filum, or Thread cirrus. Cirrus nebulosus, or Hazy cirrus. Cirrus caudatus, or Tailed cirrus. Cirrus vittatus, or Band cirrus. Cirrus inconstans, or Change cirrus. Cirrus communis, or Common cirrus. ”

“ From the base local showers of rain or snow, occasionally of hail or graupel, usually fall. Sometimes the upper margins have the compact shape of cumulus, or form massive heaps round which floats delicate “false cirrus.” At other times the margins themselves are fringed with filaments similar to cirrus clouds. This last form is particularly common with spring showers. The front of a thunderstorm of wide extent is frequently in the form of a large low arch above a region of uniformly lighter sky.
10. Stratus (St.) —A uniform layer of cloud, like fog, but not lying on the ground. ”

“ The observations of cirrus clouds in various parts of the world show that they always move from a general westerly direction, while below this primary drift toward the east occur the relatively permanent or transient differences of pressure which cause the deviations from the normal circulation of the atmosphere, and give rise to the local circulation in storms. ”

“ Falling barometer, west or southwest wind, cirrus clouds changing to cirro-stratus with high humidity.
If the change to cirro-stratus occurs rapidly, rain will probably follow within twenty-four hours.
Halos seen on successive nights indicate rain within twenty-four hours. Birds fly about wildly a few hours before a storm occurs, and men-of-war hawks, usually high fliers in clear weather, fly low in contracted circles. ”

“ It forms the mackerel sky alluded to in the following distich:—
"A mack'rel sky and mares'-tails
Make lofty ships carry low sails."
CIRRO-STRATUS. Is the stratus of the upper regions of the atmosphere, heavier looking than the cirrus, but not so heavy as the stratus.
CIRRUS. The elegant modification of elevated clouds, usually termed mares'-tails (see the distich given at Cirro-cumulus) ; otherwise the curl-cloud.
CISCO. A fish of the herring kind, of which thousands of barrels are annually taken and salted in Lake Ontario. ”

“ Falling barometer, rising temperature, cirrus and cirro-stratus clouds moving from the westward, light scud over the sea horizon moving with the surface wind, which is usually from the southwest. Humidity increases, and tides are of unusual height. ”

“ A mackerel sky, that is, one covered with lines of cirrus clouds, causing halos around the sun and moon, presages rain in summer and thaw in winter. By degrees the light clouds descend and pass into either masses of cumulus, or into dense, horizontal stratus, which form at sunset and disappear at sunrise. ”

“ These “clouds of relaxation,” if we may so call them, are usually flaky and horizontal, sometimes tending to the silky cirrus, yet showing no fine forms of drift; but when the rain has passed, and the air is getting warm, forms the true clearing cloud, in wreaths that ascend continually with a slow circling motion, melting as they rise. The woodcut, Fig. ”

“ Suffice it say that we do not now see fanciful forms in cirrus-stripes, but rather the product of threads of vapour being condensed and drawn out by currents of air 20,000 feet above the earth; and that we can often get useful information respecting coming weather by noting the direction and motion of these thin lines of hairy cloud.
Fleecy Structure.
There is another type of structure to which it is impossible to give a better epithet than fleecy. We often see a lovely, bright cloud high in the heavens that looks exactly like a sheep's fleece, and totally unlike any other cloud-form. ”

“ Whether, then, we consider the cases of clouds gradually melting away back into their original state of blue water-vapour, or the constant fine raining from clouds and re-formation by evaporation, or the transformation of such clouds as the cirro-stratus into the ripple-marked cirrus, we are forced to the conclusion that in clouds there is not always development, but sometimes degeneration; not always formation, but sometimes decay. ”

“ As cirrus begins to thicken, it will change into cirrostratus. In this form it is popularly known as “mares’ tails.” If it continues to thicken and lower, with the ice crystals melting to form water droplets, the cloud formation is known as altostratus. When this occurs, rain may normally be expected within 24 hours. The more brush-like the cirrus when the sky appears, the stronger the wind at the level of the cloud.
style="width:75%;margin-right:auto; margin-left:auto;line-height:100%;text-align:center;font-style:italic;">Figure 3614g. ”

“ Cirrus clouds always appear to move slowly, because they're so high up. As a matter of fact, they fly along at the rate of from one hundred to two hundred miles an hour, and generally in an easterly direction. This photo that looks as if the clouds were a whole pile of spiders' webs, all mixed up, is the second class of clouds, known as Cirro-Stratus. Did you happen to notice, Ralph, whether there was a halo round the sun when you took this? ”

“ He looked at the sky and saw the white cumulus built like friendly piles of ice cream and high above were the thin feathers of the cirrus against the high September sky. ”

“ Their size depends upon the temperature and the relative humidity of the air through which they fall, for, like raindrops, they increase by successive additions from the vapors with which they come in contact in descending. Thus in mild weather they are much larger than in very cold weather.
[95]
PICTORIAL CHART OF THE CLOUDS, SHOWING THEIR FORMS AND POSITION
1. Cirrus (sir ́rus) .—Small curl-like clouds, usually high in the heavens. 2. Cirro-stratus (sir-ro-strā ́tus) .—Intermediate between the cirrus and stratus. 3. Cirro-cumulus (sir-ro-kū ́mu-lŭs) .—Resembling the scales of mackerel. 4. ”

“ Early in the morning, and for the last hour, all but its heights and peaks has been wrapped in cloud-like fog. That, you discover, is thinning off, and will presently all pass away. The breeze is fresh from the north, and we will sail down upon the north-eastern side, until we have it between us and the 3 o’clock sun. We are upon soundings, and, as we glide from the broad sunny tract into the shadow of the berg, the ocean should be green, a deep green. But we have been sailing with the white ice in our eyes, and you see the ocean a dark purple. ”

“ One evening, as if drawn up by some mighty hand, the fog lifted, disclosing the sun, cold, red, and angry-looking, glaring at us out of a sombre sky, and flushing the water and the bergs round about with a flood of purple light, on which our masts and rigging cast tremulous, long, black shadows, crossing and recrossing in a quivering maze, with big, shapeless blotches here and there for the sails. ”

“ We drifted in upon the land in the chill light of a stormy dawn across a heartless cross-sea mountain high. It was dead of winter, and between smoking snow-squalls we could glimpse the forbidding coast, if coast it might be called, so broken was it. There were grim rock isles and islets beyond counting, dim snow- covered ranges beyond, and everywhere upstanding cliffs too steep for snow, outjuts of headlands, and pinnacles and slivers of rock upthrust from the boiling sea. ”

“ Familiar with clouds and sunshine, the storm and the calm, and all the phenomena which find expression in the physical geography of the sea, the right-minded mariner, as he contemplates “the cloud without rain,” ceases to regard it as an empty thing; he perceives that it performs many important offices; he regards it as a great moderator of heat and cold — as a “compensation” in the atmospherical mechanism which makes the performance of the grand machine perfect.
350. Marvelous are the offices and wonderful is the constitution of the atmosphere. ”

“ The shower, the rain, and the storm pass away, the clouds vanish, and the bright stars again shine clearly upon the glad earth. The rain-drops sink into the ground, and gather in subterranean reservoirs, and run in subterranean channels, and bubble up in springs and fountains; and from the mountain-sides and heads of valleys the silver threads of water begin their long journey to the ocean. ”

“ An occasional cloud, fleecy and jagged, sails lazily aloft, marking its shadow on the mountain side. In a few days—a few hours, perhaps—the blue sky will be unbroken, the air hushed, a hot breath will move among the leaves, or pant over the trickling fountains. ”

“ A bank of clouds, slate colored, and fringed with an ominous yellow, had gathered in the west, and there was a moaning in the air as though a far-off wind were sending a message to those in peril to beware of its breath.
The sea, too, had a glassy look. The big waves rose sullenly, and sank back into troughs, with an oily smooth motion as though they resented being thus confined. It was like the action of some raging beast in leash. There was a curious oppressiveness in the air, too, and more than one found difficulty in breathing. ”

“ You can row for miles at high tide—one view after another unfolding of wooded bays, of towering snow peaks mirrored in still waters, of forest rolling away into blue distance with great patches of scarlet on its outer fringe, and overhead soft skies with clouds for ever sliding from the sea to the mountains. ”

“ For the first five hundred miles we groped our way through fantastic wreaths of frost-fog, its dense whiteness enclosing us like a wall, and its pitiless embrace threatening to freeze the creeping blood in our veins, while, invisible, the angry currents of the fiercest tideway in the world bubbled beneath us like a witch’s cauldron, whose steam was fluid ice, after whirling us top-wise in defiance of wind and helm. ”

“ From steadfast Wind-belts, giving birth to steadfast Ocean-streams, we pass naturally to those fitful storms which lash the ocean into passing passions, and to the uncertain breezes of temperate climes.
There are currents and counter-currents, breezes and contrary breezes, winds from north and south and east and west, over the whole earth. Each separate movement of air helps to stir the waters of the sea into renewed restlessness. ”

“ Daylight found us several miles on our way to the coast, which we made, as I reckoned, about noon, to the north of where I had first landed. The cliffs here were high and rocky, the waves breaking at the foot in fountains of spray. The sky was dull and overcast, which betokened a storm. A number of white birds with yellow crests, such as I had seen on my first landing, flew inland, and several fur-coated animals, with heads resembling deer, and powerful tails, hopped across the stubble to the shelter of the trees. ”

“ The shore is encrusted with ice; the air is heavy with gloomy fogs and snow-laden clouds; the wind is blowing with searching, chilling keenness; the waters look dark as if threatening some coming calamity ”