Orographic impacts on snowfall in a narrow mountain gorge

Record snow fell over the Uncompahgre Gorge located within the San Juan Mountains in southwest Colorado during March 2010. The gorge is located near the headwaters of the Uncompahgre River and stretches from the summit of Red Mountain Pass northward through the town of Ouray. Within the gorge, a single roadway known as the “Million Dollar Highway” is the most travelled transportation corridor through the San Juan Mountains. Occasionally, major winter storms that impact the San Juans produce snowfall amounts in excess of 3 feet while the gorge below experiences little to no significant snowfall. Under certain meteorological conditions, however, snowfall amounts within the gorge will exceed 3 feet whereas the mountains will receive little to no significant snowfall. When this occurs, the highway is often shut down affecting local commerce. This phenomenon was observed during several storms during the month of March 2010 when record amounts of snow were measured at locations within the gorge. The following study will investigate the physical controls responsible for this heavy snowfall. An emphasis will be placed on the orographic challenges that this uniquely oriented mountain feature presents to forecasters.