Four Pass Loop
Elk Mountains, CO
Elevation Profile
Current Conditions
Bottom Line
Solid window for the Four Pass Loop. Low avalanche danger, normal stream flows, no fires, and a stable weather pattern with a minor snow shower chance tonight. Cold nights (24–28°F) and 31 inches of snowpack on the high passes are your main logistical factors — plan your pass crossings for late morning when the snow is firm but not icy.
45°/24°F · Partly Sunny
Low (1/5)
31" depth
Normal flows · 5 gauges
No active fires within 50 miles
14h 30m daylight · Sunrise 5:50 AM · Sunset 8:21 PM
Full Briefing
The weather is the main thing to manage here, and it's manageable. Temps drop to 24°F tonight with a 26% chance of snow showers — not a storm, just a nuisance. Expect a dusting at best on the passes. Saturday through Sunday looks clean: sunny, highs in the mid-to-upper 40s climbing to 50°F by Sunday, light westerly winds 5–15 mph. No active warnings, no red flags. This is a normal late-May alpine window.
Snowpack is the dominant terrain factor at this time of year on the Four Pass Loop. All four passes — West Maroon, Frigid Air, Trail Rider, and Schofield — sit above 12,000 feet and will still have significant snow coverage with 31 inches of depth at elevation. Low avalanche danger with no identified problems means the snow itself isn't a hazard, but you're navigating it, not just walking on dirt. The freeze-thaw cycle matters: after the cold nights (24–28°F), morning snow will be hard and potentially icy on steeper approach ramps. Target pass crossings between 9 AM and noon — the surface will have softened just enough to kick steps without turning to afternoon mush. Bring an axe or trekking poles with solid baskets; the north-facing approaches to Frigid Air and Trail Rider hold snow the longest.
Stream crossings are non-issue. All five gauges are running at or below median, and the cool overnight temps are limiting snowmelt contribution. Daytime highs in the upper 40s to 50°F won't drive aggressive melt pulses. Expect wet feet at a few crossings in the Maroon Creek and East Fork drainages but nothing requiring rope or extra caution.
With 14.5 hours of daylight, you have a generous window each day. Given the cold nights, prioritize making camp and getting your shelter sorted before dark — 24°F is cold enough to be uncomfortable if you're still fussing with a wet tent at 8 PM. No smoke, no fire closures, nothing unusual in the access corridors. Note that the SNOTEL data provided includes stations from outside this region and should not be used for snowpack interpretation — the 31-inch depth figure for the Four Pass area and the clean CAIC bulletin are your reliable references.
Waypoints
Maroon Lake
Start at Maroon Lake with views of the Maroon Bells. Take the bus from Aspen.
9,600 ft
West Maroon Pass
First pass at 12,500 ft. Views of Maroon Peak and Pyramid Peak.
12,300 ft
Frigid Air Pass
Second and highest pass. Steep approach from the Fravert Basin side.
12,500 ft
Trail Rider Pass
Third pass. Snowmass Lake visible from the descent.
12,201 ft
Buckskin Pass
Final pass with sweeping views back to the Maroon Bells.
12,300 ft
Return to Maroon Lake
Complete the loop back at Maroon Lake.
9,600 ft
Route Details
Distance
27.0 mi
Elevation Gain
10,000 ft
Elevation Loss
10,000 ft
Max Elevation
12,500 ft
Estimated Days
3
Trailhead
Maroon Lake Trailhead
Best Season
July through September. Snow on passes possible into July.
About This Route
The Four Pass Loop near Aspen, Colorado is one of the most popular backpacking routes in the state, circumnavigating the Maroon Bells-Snowmass Wilderness over four passes above 12,000 feet. The 27-mile loop can be completed in 2-4 days and offers non-stop alpine scenery. The route crosses West Maroon Pass, Frigid Air Pass, Trail Rider Pass, and Buckskin Pass, with each pass delivering panoramic views of the Elk Mountains. Between passes, the trail descends into wildflower-filled valleys with reliable water from snowmelt streams. The Maroon Bells themselves—perhaps Colorado's most iconic peaks—are visible from multiple points. The loop is best done counterclockwise, starting from Maroon Lake. Camping is available at designated sites in some valleys. The area sees heavy use in July and August. Bear canisters are required. Afternoon thunderstorms are almost guaranteed, so plan to be below treeline by noon.
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