The data set was computed using data from the National Climatic Data Center's United States Snow Climatology (TD-9641M) database (NCDC, 1999c). The original data and this element are measured to a tenth of an inch, with daily trace values designated as zero. The mean monthly values were computed by taking the 30-year mean of the sum of daily snowfall values for a given month. The mean annual value was computed by taking the 30-year mean of the yearly means. The yearly means were computed by averaging their 12 monthly mean values. Data was extracted for Arizon and 25 mile buffer.