Boulder-Grand Pass

Page Type Page Type: Route
Location Lat/Lon: 40.23950°N / 105.6632°W
Additional Information Route Type: Hike, with a small section of Class 3 at the Pass
Additional Information Time Required: A long day
Additional Information Difficulty: Class 3
Sign the Climber's Log


Begin at the Thunder Lake trailhead in Wild Basin. Follow the trail past Copeland Falls, Calypso Cascades and Ouzel Falls, along the North St. Vrain drainage. 4.8 miles from the trailhead, you will come to the Lion Lake/Thunder Lake trail junction. Continue on toward Thunder Lake, 6 miles from the trailhead.

Route Description

Using this route will take you on to Thunder Lake. At the Lion Lake/Thunder Lake trail junction, just keep going straight. You will eventually come to Thunder Lake. This lake is in a very nice spot. A Ranger Patrol Cabin and the dramatic Southeast side of Mt. Alice make for some wonderful pictures from the shores of the lake. From here begin the long ascent towards Boulder-Grand Pass in the distance. You will follow a well worn, steep, trail to Lake of Many Winds. From here follow the VERY steep and sandy slope to the crest of the pass. This will take you to just over 12,000ft, with another 1,300 feet to climb within the next mile to the summit. From the pass, it's only a Tundra walk to the top. Try not to step on the wildflowers. This is easier said than done, because they are EVERYWHERE!!! A beautiful section of the hike.

While this hike is still very steep and strenuous, there isnt as much class 3 hiking as going the Hourglass Ridge route. You will need to use your hands to help keep from sliding down the sandy trail while climbing Boulder-Grand Pass.

Essential Gear

I would recommend bringing your typical long-day hike gear (good boots, layers, rain gear, plenty of food, water, etc...). Lake of Many Winds will be your last source of water for a few hours, make sure your containers are full.

In the winter, you will need an axe and crampons. The sand at the pass is difficult enough, with snow, winter climbing gear would be a must.

Again, make sure you dont forget the camera. You will want to remember this trail.

Miscellaneous Info

If you have information about this route that doesn't pertain to any of the other sections, please add it here.

Additions and CorrectionsPost an Addition or Correction

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Timothy Pearl

Timothy Pearl - Aug 19, 2007 8:39 am - Hasn't voted

Note on Boulder-Grand Pass

Yeah, its steep and sandy! If we stick to the north side of the scree and sand there is some fun class 3 solid rock that can be climbed/descended and avoid all the erosion going on up the gut.

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