Summary (tl;dr)

A significant winter weather advisory is in effect for Colorado's mountain regions, predicting substantial snowfall and hazardous travel conditions, while the Denver metropolitan area is bracing for beneficial rain and a sharp temperature drop.

Essential Background

Colorado has experienced an unseasonably warm and dry start to the fall season. This current weather shift comes amidst a developing strong El Niño pattern in the Pacific Ocean, which historically tends to bring early-season snow to Colorado's central mountains and increased storm activity to the southern United States during winter months.

The Full Story

The National Weather Service has issued multiple winter weather advisories across Colorado's mountain ranges, with heavy snow expected to fall from Wednesday, October 14th, through Thursday, October 15th. Elevations above 9,000 feet, including crucial mountain passes and the Eisenhower Tunnel along I-70, are forecasted to receive between 6 to 12 inches of snow. Some southern and central mountain areas could see even higher totals, potentially up to two feet of snow. Travel through these high-elevation areas is expected to be hazardous due to snow-covered roads, and existing tire requirements on the main mountain corridor are in force. In contrast, the Denver metro area and the northern Front Range are primarily expecting widespread rain, though a considerable cooldown is anticipated across the entire state.

Why It Matters

This early-season snowfall is vital for Colorado's ski resorts, many of which are nearing their opening dates, and contributes significantly to the state's critical winter snowpack and water resources. However, the forecasted hazardous conditions, including snow-covered roads and potential chain and traction laws in mountain passes, will significantly impact travelers and commuters. The advisories mark the season's first significant mountain snowfall, signaling the onset of colder, more wintry conditions for Colorado.

Geographic Location

• San Juan Mountains, Colorado, United States (up to two feet of snow expected, including areas around Telluride, Silverton Mountain, Purgatory, and Wolf Creek)
• Eastern San Juan Mountains, Colorado, United States (4 to 9 inches of snow expected, including Wolf Creek Pass and Cumbres Pass)
• Jackson County, Colorado, United States (winter weather advisory for mountains above 9,000 feet)
• Grand County, Colorado, United States (winter weather advisory for mountains above 9,000 feet)
• Summit County, Colorado, United States (winter weather advisory for mountains above 9,000 feet, including the I-70 corridor)
• Park County, Colorado, United States (winter weather advisory for mountains above 9,000 feet)
• Eastern Sawatch Mountains, Colorado, United States (5 to 10 inches of snow expected above 11,000 feet)
• Western Mosquito Range, Colorado, United States (5 to 10 inches of snow expected above 11,000 feet)
• Flat Tops, Colorado, United States (4 to 8 inches of snow expected above 9,500 feet)
• West Elk Mountains, Colorado, United States (4 to 8 inches of snow expected above 9,500 feet)
• Sawatch Mountains, Colorado, United States (4 to 8 inches of snow expected above 9,500 feet)
• Berthoud Pass, Grand County, Colorado, United States (snow-covered roads and hazardous travel)
• Cameron Pass, Jackson County, Colorado, United States (snow-covered roads and hazardous travel)
• Willow Creek Pass, Grand County, Colorado, United States (snow-covered roads and hazardous travel)
• Rabbit Ears Pass, Jackson County, Colorado, United States (snow-covered roads and hazardous travel)
• Eisenhower Tunnel, Clear Creek County, Colorado, United States (snow-covered roads and hazardous travel on I-70)
• Vail Pass, Eagle County, Colorado, United States (snow-covered roads and hazardous travel on I-70)
• Monarch Pass, Chaffee County, Colorado, United States (snow-covered roads and hazardous travel)
• McClure Pass, Pitkin County, Colorado, United States (snow-covered roads and hazardous travel)
• Red Mountain Pass, Ouray County, Colorado, United States (snow-covered roads and hazardous travel)
• Molas Pass, San Juan County, Colorado, United States (snow-covered roads and hazardous travel)
• Coal Bank Pass, San Juan County, Colorado, United States (snow-covered roads and hazardous travel)
• Lizard Head Pass, San Miguel County, Colorado, United States (snow-covered roads and hazardous travel)
• Denver metro area, Colorado, United States (beneficial rain, potential for light snow at higher elevations)