Trends in 20th Century U.S. Snowfall Using a Quality-Controlled Database

A quality assessment has been undertaken of all U.S. long-term stations in which the authors have made an expert judgment on the quality of each station. Through this process, we have identified a set of stations we believe to be suitable for analysis of trends. We have analyzed snowfall variations back to 1900. Snowfall has generally decreased nationwide since peaks in the 1970s. At low snowfall stations, snowfall during the last 15 years has been lower than at any time since 1900. However, at moderate and high snowfall stations, snowfall was lower in the 1920s and 1930s. Since the late 1980s, extreme high snowfall years have been rather infrequent, while extreme low snowfalls have occurred at a near-average frequency. There are statistically significant relationships between temperature and the frequency of extreme snowfall years.