264 The National Geographic Magazine 



death and destruction in its wake, and 

 for days afterward the dead were cast 

 up by the subsiding waters and the 

 shores were lined with wreckage. Hap- 

 pily this is not now the case. The angry 

 waters and the howling winds vent their 

 fury the one upon the other, while the 

 great mass of shipping, so long the prey 

 of the winds and the waves, rides safely 

 at anchor in convenient harbors. 



The large figures in the four quarters 

 of the low again strikingly illustrate 

 how great may be the difference in tem- 

 perature, under cyclonic influence, be- 

 tween regions separated by but short 

 distances. It is certain that as the low 

 or cyclonic whirl moves toward the 

 northeast, along the track usually fol- 

 lowed by storms in this locality, the 

 cold of the northwest quadrant, by the 

 action of the horizontally whirling disk 

 of air that constitutes the low, will be 

 driven southeastward toward Florida, 

 lowering the temperature in the orange 

 groves to below the freezing point. 



Chart VI shows that the center of the 

 cyclone has moved during the preceding 

 24 hours northeast to the coast of New 

 Jersey, with greatly increased energy, 

 the barometer at the center showing the 

 abnormally low reading of 28.7 inches. 

 Cold northwest winds, as shown by the 

 arrows, are now blowing systematically 

 from the high-pressure area of the north- 

 western states southeast to Florida and 

 the South Atlantic coast. The red iso- 

 therm of 30 degrees passes through the 

 northern part of Florida, where, on the 

 day before, the temperature was over 

 50 degrees. The cyclonic gyration of 

 this storm extends 1,000 miles inland 

 and probably to an equal distance out 

 to sea. Heavy snow or rain has fallen 

 throughout the area under its influence, 

 seriously impeding railroad travel, and 

 a gale of hurricane force has prevailed 

 on the coast ; but when, on the day pre- 

 ceding, the storm was central in Ala- 

 bama all these conditions were foreseen 

 and the necessary warnings issued. 



Chart VII shows the conditions 24 

 hours later. The storm center, as shown 

 by the line of arrows, has been three 

 days in passing from southern Texas to 

 the mouth of the St Lawrence. The 

 temperature has fallen still lower on the 

 Atlantic coast and in Florida as the re- 

 sult of uninterrupted northwest winds, 

 and no material rise in temperature can 

 occur until the high pressure of the 

 northwest is replaced by a low pressure, 

 and convectional currents are drawn to- 

 ward the northwest instead of being 

 forced southward from that region. 



When the charts indicate the forma- 

 tion of a large volume of dense, cold air 

 in the northwest, as shown by the ba- 

 rometer readings, the skilled forecaster 

 is on the alert. He calls for special 

 observations every few hours from the 

 stations within and directly in advance 

 of the cold area, and as soon as he be- 

 comes convinced that the cold wave will 

 sweep across the country with its at- 

 tendant damage to property, destruction 

 to animal life, and discomfort to human- 

 ity, the well- arranged system of dissem- 

 inating warnings is brought into action, 

 and by telegraph, telephone, flags, bul- 

 letins, maps, and other agencies the 

 people in every city, town, and hamlet, 

 and even in farming settlements, are 

 notified of the advancing cold 12, 24, or 

 even 36 hours before it reaches them ; 

 and it is safe to say that $10,000,000 

 is a low estimate to make of the value 

 of the perishable property that is pro- 

 tected in the United States as the result 

 of the warnings that are distributed by 

 the government in advance of the com- 

 ing of only one of several severe cold 

 waves that occur each winter. 



In the late spring and early fall the 

 highs or anti-cyclones, while possess- 

 ing less energy than in the winter, may 

 at times bring down to the earth such 

 unseasonably cold air as to cause inju- 

 rious or destructive frosts, the frosts 

 being caused not necessarily by the cool 

 air of the high, but by the clearness of 



