in turn imparts to the air above it a temperature of 100° F. or more. If the wind continues for several days it evaporates the moisture from the soil, and vegetation in consequence is parched.
Mistral, or Cold Winds. --After the passage of an area of low barometer over southern Europe in winter, the advance of an area of high pressure over northern Europe frequently causes cold northerly winds to penetrate to the Mediterranean. In southern France they are called the mistral, and on the Adriatic Sea the bora. A similar wind, except that it is from the south, is called the pampero in Argentina, and the southerly burster in Australia. The Texas norther also belongs to this class.
After the passage of a low-pressure area from the region of the Gulf to the Atlantic coast an area of high pressure sometimes appears in the upper Missouri or Mississippi valley. The result is a steep barometric gradient from the north to the south. In addition the usual winter temperature gradient is augmented, since the cyclone has caused warm south winds over the Gulf States, while the anticyclone has caused an inflow of cold air from the north. Furthermore, the topography of the country favors air drainage from the north to the south. The result is a cold northerly wind, which is especially severe over Texas, sometimes causing a fall in temperature comparable with the rise in temperature that accompanies the chinook. This wind may or may not be accompanied by rain or snow. Similar winds usually herald the advance of the familiar cold waves of the central valleys and the Atlantic coast. In the Dakotas this wind is sometimes accompanied by blinding snow, which, combined with the extreme cold, makes it especially destructive to animal life. It is locally called the blizzard. The buran and the purga, which occur on the steppes of central Asia, have the characteristics of the blizzard.
The above-described winds are typical of many others that might be named.
Hurricanes, typhoons, tornadoes, simooms, and thunderstorm gusts are discussed in other chapters.
MARVIN C. F., "Anemometry," 3d ed., Washington, 1907. ( United States Weather Bureau, Circular D, Instrument Division.)
FERREL WILLIAM, "A Popular Treatise on the Winds," New York, 1889 (and later reprints).