Debris Flow in San Juan County, Colorado

Rock falls occurred along Highway 550 near the Red Mountain Pass snowshed which is between mile markers 87 and 88, due to significant rainfall reported around 1000 MST on October 11.

Between October 10-14, 2025, southwest Colorado experienced prolonged periods of rain and some of the largest multiday rainfall totals on record with rainfall accumulations between 3 and 8 inches, with locally higher amounts across the San Juan Mountains. Remnants from two tropical storms supplied anomalous moisture across the region, with minimal break between events. The first round of heavy rainfall resulted in flooding across La Plata and Archuleta counties from decaying Tropical Storm Priscilla beginning October 10 and continuing throughout the day on the 11th. There was a break in rain across the area on October 12, followed by a second round of heavy rain from October 13-14, associated with moisture from remnant Tropical Storm Raymond. Without much time between systems, the hydrologic response of the second storm was much faster than the first. Flooding across several counties in southwest Colorado spiked twice within the 5-day window, leading to major flooding and near record peaks along the Vallecito, Piedra and San Juan watersheds that lingered through the 16th before water levels receded. Numerous debris flows and rockslides also occurred as a result of the abundant rainfall.