Snowdown Balloon Rally Mass Ascension – Sylvia’s Air Park in the Hermosa Valley. Visiting balloon pilots will launch together in a traditional mass ascension from this scenic airpark near Durango, Colorado. About 30 hot air balloon pilots traveling from out of state will rise side by side, creating one of the most photographed moments of Snowdown. Spectators are invited to gather about 8:30 in the morning to watch the inflation process, visit with the crews, and enjoy the sight of balloons lifting into the winter sky. Launches will depend on safe winter weather conditions.