248 THE WEATHER 



VI. THE GENERAL STORM 



273. The General Storm ; How It is Studied. The weather 

 features thus far considered may be studied by one person 

 working alone. The widespread storms of the country can 

 not be understood unless we have observations taken at the 

 same time at many different places. To study such storms 

 and to predict their coming, many countries have weather 

 services with a large number of stations that take simulta- 

 neous observations and telegraph them immediately to a cen- 

 tral office. There the weather conditions at all stations are 

 charted on a large map. The map is thus a bird's eye view, 

 and shows the regions of storm and of fair weather, the areas 

 of rising temperature and of falling temperature, and all other 

 important features over the entire country. In the United 

 States, the weather maps cover our own country and the in- 

 habited portions of Canada, and are made both morning and 

 evening. The forecasters study the maps. They see how 

 the weather conditions are developing and traveling, and 

 then publish the forecasts of what weather they expect will 

 occur in each state during the next 36 to 48 hours. 



The U. S. Weather Bureau distributes its forecasts to all parts of the 

 country within a few hours. At more than 100 cities daily weather 

 maps are printed and distributed, giving more complete information 

 to the public. The daily temperature and rainfall observations of 

 4000 cooperating observers, located in almost every county of the 

 entire country, are worked up each month and year and published in 

 convenient form for the use of everyone desiring the weather informa- 

 tion of any section. Special warnings of frosts are furnished to farm- 

 ing, fruit and gardening interests, and cold wave warnings to rail- 

 roads, to shippers, and to many other interests. Warnings of gales 

 on coasts and lakes are sent to shipping offices and to ships. The 

 rivers are watched, and warnings of floods sent, to guard against 

 damage by high water. The accumulated snow of the mountains is 

 measured for the irrigation projects of the west, to show the amount of 

 water available for the coming season. Scientific problems related 

 to weather and climate are studied in search of other ways of assisting 

 the public. The saving to the business of the country each year 

 through the work of the Bureau is several times its total cost. 



