Observing Deep Hail Accumulations on the Colorado and Wyoming Front Range

Hail accumulations from thunderstorms, sometimes as large as 60 cm in depth, have significantly affected the populations across the High Plains of Colorado and Wyoming by creating hazardous road conditions and endangering lives and property. Despite the extreme nature of these thunderstorms, no mechanism is currently in place to obtain comprehensive reports, measurements, or forecasts of accumulated hail depth. To better identify and forecast hail accumulations, the Colorado Hail Accumulation from Thunderstorms (CHAT) project has been initiated with the goals of collecting improved and more frequent hail depth reports on the ground. This presentation will introduce the CHAT project and provide some preliminary results. We will highlight how a database of hail depth reports is used to study and identify the characteristics of storms that produce deep hail accumulations in Colorado, as well as present methods to nowcast these events, including a newly developed and validated operationally viable radar-based hail accumulation algorithm. With the new hail accumulation algorithm, hail accumulation data have been analyzed between 2013 and 2017 along the Colorado Front Range yielding knowledge about hail accumulation frequency and hail depth distributions in this area.