BOTANICAL SURVEY— SUGAR GROVE REGION 



importance because of the destructive effects of the floods, which would 

 fix the boundaries of the flood-plain associations subject to inundation 

 and prevent permanent encroachment upon these associations by the 

 plants of higher ground which could not endure the flood. 



AVERAGE MONTHLY RAINFALL (INCHES) 



The average snowfall is very close to 25 inches (62.5 cm.). The 

 configuration of the land is such that the snow is generally blown or 

 melted off the uplands, leaving them bare and exposed for the most 

 of the winter. The depth of the annual snowfall is an insignificant 

 factor in such situations, but in the deep ravines the drifts accumulate 

 and keep them cold and wet well into the spring, affording thereby 

 suitable habitats for the many northern plants, which here reach their 

 southern limits. Single snowfalls exceeding 8 inches (20 cm.) are not 

 common, but there is a record of 30 inches (76 cm.) at Lancaster 

 during April, 1901. At Columbus 13.5 inches (39 cm.) is the greatest 

 amount of snow ever reported upon the ground at one time. The 

 greatest annual snowfall of record is 67.8 inches (170 cm.) in the 

 winter of 1909-10, while the smallest is 8.5 inches (21 cm.) in the 

 winter of 1896-7. Snowfall is usually confined to the months from 

 November to April, but "appreciable depths of snow sometimes occur 

 in May and October." 



"The average number of rainy days is 106. The average numl)er 

 of clear days is from 125 to 150, and the average number of cloudy days 

 is about the same. At Columbus the average annual sunshine is 54% 

 of the possible amount ; the average number of clear days is 103, partly 



