Clouds (1938)

[Music] clouds are the visible evidence of processes taking place in the air the garments of the weather so to speak which change continually as the weather changes in fact the changes of the cloud garments in many cases precede and foreshadow changes in the weather thus the cloud is not only one of the most beautiful and inspiring of the manifestations of nature but it is of practical value as well for it indicates the probable weather conditions for the immediate future indeed if you know your clouds well enough you can do a pretty fair job of forecasting for per perhaps a day ahead subject of course to upsets due to factors beyond Jan for ages Farmers hunters and Mariners have used clouds as weather signs changes in weather and in Cloud forms are due to the passage of different air masses associated with wind systems called Cyclones this two Cyclone not to be confused with a tornado is a great counterclockwise wind 2,000 m in diameter moving from west to east about 600 M A Day the center of this advancing WHL is a point of low barometric pressure between areas of higher pressure or anticyclones cold air masses are usually found east north and Northwest of the center with a warm sector to the South thus we have a warm front with easterly shifting to southerly winds then a warm sector with southerly winds followed by a cold front with wind shifting to Northerly where War moist air overrides cold air there is precipitation rain or snow taking a vertical section through this diagram and changing our Viewpoint we can illustrate the progress of these fronts starting at the axis of the anticyclone where the barometric pressure is high let us watch for three or 4 days while the Cyclone passes think of the space above this imaginary warm front line as filled with a mass of advancing warm air flowing up over a dome or r of heavier cold air this warm air is moist and as it is lifted and cools different Cloud forms develop at different altitudes as the warm front at the Earth's surface approaches there is rain or snow this precipitation is generally steady and light to moderate fair weather follows as we enter the warm sector here warm air ascends by convection owing to the heat of the Sun and presently clouds begin to form as the weather grows warmer these clouds grow heavier and as the warm sector passes and the cold front approaches they become dense and threatening culminating in heavy rain as the cold front passes this is the so-called Squall line then the clouds tend to dissipate as the Northwest winds bring in cold descending air and finally we are back to where we started in a high pressure area so much for the phases of the typical weather cycle which is most pronounced in Winter less so in Spring and fall and often interrupted in summer now let's study the types of clouds that usually Mark the progress of such a cycle starting after the passing of a cold front we have cirrus clouds sometimes called May's Tails these wispy clouds of ice particles are the highest of all floating at an elevation of 25 to 30,000 ft above the Earth the wind is from the Northwest barometer high temperature cool Cirus clouds may be followed by C Stratus which may merge into cumulus sometimes called macro Sky next not quite so high we may have aloc cumulus clouds meanwhile the wind is Northerly temperature cool barometer still high lower down on the frontal slope we encounter Alto stratus clouds generally with Northeast winds balling barometer and steady or slowly Rising temperature as the warm front approaches the wind swings to the east with nimbus clouds and rain or snow as the warm front passes the wind veers to a southerly direction bear in mind that shifts in Wind give a general indication as to what sector of the Cyclone we are entering then the sky clears and we have fair and warm weather for perhaps a day with Southwest winds and steady or slowly falling barometer scattered cumulus clouds appear at an altitude of 5,000 ft or more gradually becoming heavier as the temperature rises as the cold front approaches the clouds often rise suddenly into threatening thunderheads mountains of cumulon nimbus clouds towering to a height of possibly 30,000 ft as the tip of the sloping cold front arrives nimbus clouds form at the base of the cumulon Nimbus storm cloud and heavy showers occur this is normally a brief but violent rainstorm while the cold front is passing the temperature Falls abruptly the wind shifts to the Northwest the barometer r Rises and we may have a rainbow soon thereafter the storm clouds give way to fracto cumulus clouds that rapidly dissipate thus we come back to the sector of fair and cool weather and the cycle is complete so much for the Practical aspect of clouds the aspect that outdoor men study daily for indications of the weather the beauty of the cloud is quite another matter yet one of prime importance to the human Spirit indeed there is no one feature of the average landscape that may add more to its charm and appeal than beautiful clouds try to make a worthwhile picture of a flat plane like this without clouds in the sky and you begin to realize the aesthetic importance of clouds in this world of ours and even when they are not inherently beautiful clouds may have much charm and interest the fog that drifts over the peak of Mount tamop the merely a gray Mist to The Observer on the mountain has an appeal to the lover of nature an appeal which may be heightened by the knowledge that the altitude of the Observer has much to do with the type of cloud as it is revealed to his eyes thus one man's fog may be another man's Stratus from San Francisco this fog appears as a high stratus cloud encircling the top of a distant Mountain from the slope of Pike's Peak at Sunrise we look out over a sea of fog stretching level and unbroken to the Horizon if we were in Colorado Springs 2,000 ft below this fog would be a broken sheet of low stratus clouds which would soon be dissipated by The Heat Of The Morning Sun as we look at this view of Mount Hood the cloud we see is a streak of fracto cumulus to the mountain climber it is a fog thus these fracto cumulous clouds about the summit of Mount shter though they look Serene and to us sweep over the glaciers of that lofty Peak as a cold and forbidding mist from all this it appears that we might well take our cloths more or less seriously though most of us cannot hope to acquire the instinctive Weather Wisdom of the born hunter or sailor to whom the sky is an open book we may at least find pleasure and perhaps some profit in trying to understand those riddles written in Vapor that pass overhead day onto Day utth speech and night onto night showeth knowledge and to be able in some measure to interpret that speech is to have a fuller appreciation of the significance and beauty of the cloud a Keener sense of the Majesty of the Gathering storm of the Splendor of the sunset of the incalculable variations in color and form that lend meaning and Beauty to the Magnificent pageantry of the weather cycle [Music] [Music] [Music] [Music] [Music] [Music] is [Music]