A Rocky Mountain Storm. Part II: The Forest Blowdown over the West Slope of the Northern Colorado Mountains—Observations, Analysis, and Modeling

Abstract

Abstract A devastating winter storm affected the Rocky Mountain states over the 3-day period of 24–26 October 1997. Blizzard conditions persisted over the foothills and adjoining plains from Wyoming to southern New Mexico, with maximum total snowfall amounts near 1.5 m. (Part I of this two-part paper describes the observations and modeling of this blizzard event.) During the morning of 25 October 1997, wind gusts in excess of 50 m s−1 were estimated west of the Continental Divide near Steamboat Springs in northern Colorado. These winds flattened approximately 5300 ha (13 000 acres) of old-growth forest in the Routt National Forest and Mount Zirkel Wilderness. Observations, analysis, and numerical modeling were used to examine the kinematics of this extreme event. A high-resolution, local-area model (the Regional Atmospheric Modeling System) was used to investigate the ability of a local model to capture the timing and strength of the windstorm and the aforementioned blizzard. Results indicated that a syne...