WEATHER CHANGES 



173 



wave is accompanied by snow, it is called a blizzard, and on 

 the plains and prairies, where the wind has a clear sweep, 

 it is much dreaded. Cattle and men, when caught in it, 

 frequently perish. In southern Europe the coldest winds 



are from the Siberian plains and are therefore northeasters. 

 In the United States the cold area is at the southwest and 

 rear of the cyclone, whereas in Europe it is at the north 

 and front. 



When, instead of the strong, cold northwest winds 

 which blow into the rear of a cyclonic area and in the 

 colder seasons may produce a cold wave, there is a pro- 

 longed movement of highly heated air from the south into 

 the front of the low pressure, as sometimes occurs dur- 

 ing the warm months, the "hot spells of summer" are 

 caused. The air is sultry, exceedingly hot and oppressive. 

 Sunstrokes and prostrations from heat are common. 

 The " hot winds " of Texas and Kansas, the Santa Ana 

 of lower California and the siroccos of southern Italy 

 are intensified examples of these winds. All sudden 



