MARYLAND GEOLOGICAL SURVEY 203 



1897. It appears from the table that droughts of 10 days' duration or 

 more have occurred at Solomons 53 times in the last 13 years. 



Durino^ the same time the number of times rain has fallen on 5 or 

 more consecutive days was only 19. Eain on 4 days or more occurred 

 25 times. These exclude traces not considered as rain. The longest 

 duration of rainy days is 7, viz., April 27 to May 3, 1895, during which 

 time 3.88 inches fell, and July 17 to 23, 1897, with 3.63 inches. The 

 heaviest rainfall during any of the rainy periods above recorded was 

 5.86 inches from August 8 to 12, 1898. 



The average number of days on which 0.01 inch or more of rain falls 

 at Solomons is 108. July has the largest number of rainy days (12), 

 September the least (6). The probability of rain in summer is 0.4; 

 in late winter and spring 0.3, and in autumn only 0.2. 



When rain occurs the average amount received each rainy day (or the 

 intensity oi rainfall) is as follows: 



Intensity of Rainfall at Solomons. 

 Jan. Feb Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. 

 0.28 0.3S 0.33 0.35 0.34 0.36 0.40 0.41 0.44 0.44 0.30 0.36 



Snowfall (Unmelted). 



The heaviest snow storms in southern Maryland are invariably asso- 

 ciated with the Gulf type of barometric depressions, which move north- 

 eastward from the Gulf of Mexico over the Atlantic States or along the 

 coast line; light snow also frequently falls after the passage of other 

 depressions over or near the boundaries of the State, but only after the 

 shift of the wind to west or northwest. This statement is borne out by 

 the direction of the prevailing winds during snow storms in Calvert 

 County, which is frequently northeast or north to northwest, but very 

 rarely from any southerly and easterly direction. The annual snowfall 

 (unmelted) at Solomons is presented in Table XV. 



The annual total is about 18 inches. As several winters have recently 

 been very severe, this amount is probably above the true normal for this 

 region. Small amounts of snow may fall in April and ISTovember, usu- 

 ally less than an inch, while the largest averages occur in January and 

 February, 6 inches. Snow falls on the average on 17 days each year. 



