Monarch Pass

Monarch Pass carries US-50 over the Continental Divide at the south end of the Sawatch Range in central Colorado, on the Gunnison/Chaffee county line. The summit sits at 11,312 feet (USGS GNIS, via Wikipedia). The pass is about 20 to 25 miles west of Salida. It ties the upper Gunnison River basin on the west to the South Arkansas River drainage on the east. Monarch Mountain ski area straddles the highway right at the divide crossing, so in winter ski traffic climbs the same grade as the trucks.

Both descents are long and steady, not gentle. The east side toward Salida runs about 10 miles at 6 percent. The west side toward Gunnison runs about 9 miles at 6 percent, with some reports of pitches up to 7 percent (Wikipedia). The road is curve-heavy on the way down. Wikipedia lists ten curves advised at 35 mph and one at 30. The truck-specific safe descent speeds tell the story. Crash Forensics figures put a 50,000 lb truck at about 45 mph and an 80,000 lb truck at just 15 mph (cited in Wikipedia). On the longer east grade that means a real risk of cooking your brakes if you let the speed creep.

CDOT keeps the pass open year-round and it is generally open, but it closes on short notice for snow removal and avalanche control during storms. The top is violently exposed. The summit AWOS station once recorded a 148 mph gust, the highest official wind gust ever logged in Colorado (NWS Pueblo). A CDOT station 700 feet lower read 32 mph at the same moment, which tells you how local and how brutal the wind at the top can get.

• Summit 11,312 ft on US-50 over the Continental Divide, on the Gunnison/Chaffee county line (USGS GNIS, via Wikipedia)
• East descent toward Salida runs about 10 miles at 6 percent; west descent toward Gunnison about 9 miles at 6 percent, with reports up to 7 percent (Wikipedia)
• Ten curves advised at 35 mph and one at 30; safe descent speed about 45 mph for a 50,000 lb truck, 15 mph for an 80,000 lb truck (Wikipedia, citing Crash Forensics)
• Commercial chain-up corridor of multiple lit stations on US-50 between mile points 189 and 211 across Chaffee, Gunnison and Saguache counties (CDOT; TheTrucker.com)
• Commercial vehicles must carry chains Sept 1 to May 31, even when no law is active (Colorado State Patrol; CDLLife)
• Roughly 240+ inches of snow a year; the ski area at the summit reports about 400 inches (Wikipedia, NOAA data; Wikipedia 'Monarch Mountain')
• Summit AWOS once clocked a 148 mph gust, Colorado's highest official wind gust on record (NWS Pueblo)

Colorado runs a tiered Traction/Chain Law on US-50 over Monarch Pass, and CDOT turns it on as conditions get worse. Under the commercial Chain Law (Code 18), every commercial vehicle rated 16,001 lb or more has to chain up. Single-drive-axle and tandem-drive-axle combinations chain four drive wheels, buses chain two, and autotransports chain to the extent they can without damaging hydraulic lines (Colorado State Patrol; CDLLife). Even when the law is not active, commercial drivers have to carry adequate chains on this corridor from September 1 through May 31. That carry requirement is the same statewide rule applied on stretches like I-70 mileposts 133 to 259, and it extends to US-50 (9news.com; CDLLife; CDOT). The fines stack up fast. Not carrying chains in the Sept 1 to May 31 window is $50 plus a $17 surcharge. Failing to chain when Code 18 is in effect is $500 plus a $79 surcharge. Blocking the highway because you did not chain is $1,000 plus a $157 surcharge (Colorado State Patrol).

CDOT runs a dedicated chain-up corridor of multiple lit stations on US-50 between mile points 189 and 211, spanning Chaffee, Gunnison and Saguache counties. A 2021 project (contractor Tricon 2, LLC) added new lighting, some of it solar, widened and paved five of the station locations, and replaced two culverts (CDOT; TheTrucker.com). For closures, CDOT uses Sargents (around MP 190) and Maysville (around MP 210) as the standard east and west gates. There is no single published per-season closure count from a primary source. CDOT shuts the pass as needed, usually for planned overnight or early-morning snow-removal windows and for avalanche-control work during storms and warm-up thaw cycles. Documented examples: a Jan 24, 2026 closure from 4 a.m. to 6 a.m. between MP 200 and 210 for safety-critical winter maintenance, and a Feb 9, 2024 closure starting at 5 p.m. for about two hours between Sargents (MP 190) and Maysville (MP 210). CDOT says closure length varies with the weather, snow accumulation and avalanche danger. Avalanche-control closures typically run up to about three hours. A widely repeated estimate of roughly 15 to 25 closures per winter shows up in web summaries, but no CDOT primary source confirms it, so treat it as unverified. Check COtrip.org for live status before you climb.

The current crossing is the third Continental Divide alignment to carry the Monarch name. An 1880 toll road crossed the original pass, a 1922 realignment created what is now Old Monarch Pass, and a 1939 realignment moved the crossing about 0.6 miles southeast to today's US-50 summit (Wikipedia). The new US-50 over the divide was finished except for paving in November 1939. It was first designated Vail Pass, but after local objections Governor Ralph Carr officially named it Monarch Pass in December 1939.

Monarch ski area went up alongside the new highway during the Depression. A 500-foot rope tow powered by an old oil-derrick gearbox and a Chevy truck engine ran in 1936, the WPA funded the initial construction with a $26,000 grant, and the Monarch Winter Sports Area was dedicated in February 1940 (Wikipedia 'Monarch Mountain'; skimonarch.com). The summit set a state record decades later. On February 17 and 18, 2016, the AWOS station above the pass clocked a 148 mph gust that NWS Pueblo and the Colorado Division of Aeronautics confirmed as the highest official wind gust ever recorded in Colorado, beating the prior 147 mph mark set at Boulder in 1971.