* WHAT...Heavy snow expected above 10, 000 feet. Total snow accumulations between 12 and 18 inches, with locally higher amounts possible. Winds gusting as high as 45 mph. * WHERE...Northwest San Juan Mountains and Southwest San Juan Mountains. * WHEN...From 6 AM Sunday to noon MST Monday. * IMPACTS...Travel could be very difficult to impossible. The hazardous conditions will impact the Monday morning commute.