HYDROLOGY OF NEW YORK 



49 



which, although several hundred feet higher, has a rainfall con- 

 siderably less than that at Rochester. 



In the southeastern portion of the State the ocean winds find 

 no obstruction along the coast, but, passing inland and meeting 

 the abrupt ranges of the southeastern counties, give a copious 

 rainfall as compared with that of the intervening regions. 



Western New York, on account of the frequent southwesterly 

 direction of the winds, receives an appreciable portion of its 

 vapor supply from the Gulf of Mexico. The rainfall in central 

 New York, although less than that of the southeastern and south- 

 western highlands, is generally abundant. The principal valleys 

 of the Susquehanna system, and also the depression of the central 

 lakes tributary to Oswego river, show a deficiency as compared 

 with the average of the State. 



A knowledge of the snowfall is important in a study of the 

 water resources, because by reason of the snow lying on the 

 ground continuously for several months it is a great source of loss 

 in open regions subject to severe winds, the evaporative effect of 

 the winds tending to carry away large quantities of moisture 

 which would otherwise be available to maintain stream flow. 

 Thus far the only data relating to depth of snow are those derived 

 from the Reports of the State Meteorological Bureau. The follow- 

 ing are a few figures so derived : In the winter of 1893-94 the total 

 depth of snow at Humphrey, in the western plateau, was 136.5 

 inches ; in 1890-91 the total depth at Cooperstown, in the eastern 

 plateau, was 110 inches ; in 1891-92 the total depth at Constable- 

 ville, in the northern plateau, was 170.7 inches; in the winter of 

 1890-91, at Utica, in the Mohawk valley, the total depth was 165 

 inches, and in 1891-92, at the same place, 151.6 inches. The 

 records show that at the places where these large snowfalls oc- 

 curred the ground was continuously covered with snow for sev- 

 eral months. If the winds were of high velocity at the same time 

 the evaporation loss must have been very great. 1 



Division of the State into climatic areas. In 1891 the State Me- 

 teorological Bureau divided the State into ten subdivisions, 



!For extended discussion of climate of New York see a monograph by 

 E. T. Tanner, in 8th Rep't New York Weather Bureau. 



