Investigating the Role of Two-Inch Soil Temperatures in Snowfall

This project investigates the impact two-inch soil temperatures have on snowfall accumulation as well as the impact snowfall rates and accumulation have on soil temperatures. In operational forecasting, there is an assumption that soil temperatures play a vital role in whether or not significant snowfall accumulations are possible. Although this supposed relationship has been used by many forecasters in their decision process, research to support this assumption is sparse. After a thorough literature search, only three cases of this soil temperature-snowfall relationship were found, none of which were peer-reviewed. Most recently, Michael Fowle, the Science and Operations Officer at the Aberdeen, South Dakota Weather Forecast Office has been giving attention to this relationship. His preliminary investigation led to the formation of this project. The project specifically examined a main question with two supporting questions. The main question: what role do soil temperatures play in snowfall? The supporting questions: is there a threshold value of two-inch soil temperature at which accumulation is possible? What role does snowfall rate play in this relationship? This project utilizes direct observations and examination of individual cases of snowfall to answer these questions. The results of this project show the relationship between soil temperature and snowfall and how these results can impact forecaster ability to predict accumulations. This project was carried out at the National Weather Service Weather Forecast Office in Cheyenne, Wyoming.