SOME WEATHER MISCELLANIES
THE EFFECTS OF AN ICE STORM AT CANTON, N. Y.
March 25-27, 1913
It would require a book, rather than a brief essay, to describe all the vicissitudes of weather, and many books that attempt to do this have been written.[A] We have space here only to mention a few important features of the weather met with in our own country.
The southern and southeastern part of a cyclone, some hundreds of miles from the center, is a favorite breeding-ground for thunderstorms and tornadoes. Thunderstorms of the type known as "heat thunderstorms" also occur with no special relation to cyclonic centers in regions where the ground has been intensely heated. In either case the storm is built up by rapidly ascending air, which cools and condenses its water vapor, first into enormous clouds (cumulo-nimbus, or "thunderheads"), and then into rain, frequently accompanied by hail. It would be necessary to go to some length to explain the familiar electrical manifestations of the thunderstorm—some points, indeed, are not perfectly clear to meteorologists—but it should be stated that these are always the result, not the cause, of the storm. Lightning is an electrical discharge between cloud and earth, or cloud and cloud, and thunder is simply the violent soundwave set up by the sudden expansion of the heated air along the path of the discharge,—the same acoustic phenomenon that accompanies an ordinary explosion.
SUMMIT HOTEL AT SUMMIT, CAL.
On March 18, 1911. A three-story building whose first story is buried under twenty-six feet of snow
Courtesy of the Scientific American
A tornado (popularly miscalled a "cyclone") is an extremely violent vortex in the air, usually less than 1,000 feet in diameter. Besides its very rapid rotary motion, it has a progressive motion at a speed averaging forty or fifty miles an hour. Its position at any moment is marked by a black funnel-shaped cloud, which grows downward from the sky and does not at all times reach the earth. A waterspout at sea is an identical phenomenon, though usually less violent. Along its narrow path the tornado demolishes everything,—wooden houses are blown to splinters, trees uprooted or stripped of their branches, structures of heavy masonry laid in ruins. Something like a hundred lives are lost each year in these storms, on an average, and one of them (St. Louis, May 27, 1896) destroyed thirteen million dollars' worth of property.
TURPAIN'S THUNDERSTORM RECORDER
Or ceraunograph. This is one of several instruments designed to register the natural electric waves, or "strays," which sometimes interfere seriously with the transmission of wireless telegrams. Strays are often generated by lightning discharges, near or distant, and this instrument therefore serves to give notice of an approaching thunderstorm
A blizzard is a high, cold wind, accompanied by blinding snow, which in winter sometimes blows out of the front of an advancing anticyclone, especially in our North-Central States. A similar wind, with or without snow, is called in Texas a norther.
A chinook is a warm, dry wind that descends the eastern slope of the Rocky Mountains in Montana, Wyoming and Colorado, and flows north-eastward over the plains. Its effects are most pronounced in winter, when it brings about a very sudden rise in the temperature—in extreme cases as much as forty degrees in fifteen minutes! It causes snow to vanish as if by magic, and is appropriately nicknamed the "snow-eater."
IN THE WAKE OF A TORNADO
The tornado destroyed a house and barn, but left a path in the center with practically no harm done
"Cloudburst" is merely a picturesque name for a very heavy shower; usually a thunder-shower.
West India hurricanes occasionally visit the United States, especially in the late summer and early autumn. These storms begin as violent cyclones of small extent (300 to 600 miles in diameter), usually somewhere east of the West Indies, sweep in a long curve across the Caribbean Sea, and then turn north, either passing up along the Atlantic Coast or crossing the Gulf of Mexico into the southern United States. Soon after entering the temperate zone they increase in size and diminish in violence, but are still vigorous enough on reaching the Gulf or South Atlantic Coast to cause great devastation. Low-lying shores are often inundated by the immense waves they generate.
LOOKING DOWN ON A SEA OF FOG FROM MT. TAMALPAIS, CALIFORNIA
Cold waves are the rapid and severe falls in temperature that sometimes occur in winter, especially at the front of an anticyclone. Warnings of these occurrences, issued by the Weather Bureau twenty-four to thirty-six hours in advance, often result in the saving of millions of dollars' worth of merchandise susceptible to damage by freezing.
Frosts in the spring and autumn are also predicted with great success, to the immense advantage of farmers, market-gardeners, and horticulturists. The practice of smudging or heating orchards, now so widespread, is usually carried on under the advice of the Weather Bureau, which gives prompt notice to the orchardist when such precautions are in order. The bureau publishes charts showing the average and extreme dates of the last frost in spring and the first frost in autumn for all parts of the country.
A fog is a cloud resting on the surface of the earth. In the United States fog is commonest along the northern and middle parts of the Atlantic and Pacific Coasts. In the interior of the country, especially the western part, it is of rare occurrence, the average number of days a year with fog being less than ten.
Lastly—weather fallacies are rife. Indian summer is merely a type of mild, hazy, heavenly weather that prevails intermittently during our long American autumns. The equinoctial storm is a myth; the climate has not "changed" anywhere within the span of a human lifetime (one year differs from another, but there is no progressive or permanent change); and the moon has nothing whatever to do with THE WEATHER.
[A] See "Brief List of Meteorological Textbooks and Reference Books," 3d ed., by C. Fitzhugh Talman. For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents.