HAIL INSURANCE ON FARM CROPS. 



13 



Some idea of the relative importance of the hail hazard in differ- 

 ent parts of the country ma.j be obtained from figure 3, which indi- 

 cates in a general way the frequency of the occurrence of hail in the 

 United States during the four months, May, June, July, and August. 

 The data represented on this map are based on reports from the vari- 

 ous United States Weather Bureau stations, and cover the 14-year 

 period 1906-1919, inclusive. The map or chart in question, it should 

 be emphasized, indicates only the average annual frequency of the 

 occurrence of hail during the months stated, no attempt having been 

 made to allow for differences in the severit} 7 or the destructiveness 

 of hail storms. It should perhaps also be pointed out, as has been 

 done by the Weather Bureau in connection with earlier published 



F 



1.0 





AVERAGE NUMBER OF DAYS WITH HAIL 

 MAY TO AUGUST INCLUSIVE 

 i906 1919 













\ 1 ^^~\ \ "^o^ ^> 













• ~^l \ \ 







\° V-^~"A. 









I "t^ 























V v"-i 





B± 









-~k 



/ 1 ->oT L ~i 











\^ 













~"\ ^-1 — ■ — \ / 















Vj «.,»„ BU R EAU . u S D » 







Fig. 3. 



data on this subject, 1 that the reports on which the chart is based 

 come from only 167 stations rather unevenly distributed throughout 

 the United States. Since hail storms are frequently very local in 

 character, it follows that the data as represented embody an element 

 of chance even as to the average frequency of hail. It is probable, 

 for example, that the total number of times at which hail occurred 

 and, hence, also the average yearly number of such occurrences re- 

 ported from a given station, may represent either more or less than 

 the average frequency for all parts of the area for which such station 

 is considered a center. 



To a certain extent the relatively long period of time covered by 

 the reports will, of course, tend to eliminate some of the chance ele- 

 ments involved in the lack of a sufficient number of reporting stations. 



1 See Weather Bureau Review for March, 1917, pp. 94 et seq. 



