Summer Sliding Below the East Face of Longs Peak

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 Approx. 1500′ vertical from  13.2K  to 11.8k  – Chasm Lk.)

Avg. Angle:  40

Steepest Angle:  45

Technicality:  Generally 3rd class when in skiable shape- no ropes needed.

Avg Tour Length:  7-10 hrs.  car to car.

Typical Avi Danger:  Many D2-3  sluffs during and after storms plus soft slab potential in upper layers are the  most common hazards.  

Snowpack is typically deep (4-7 m) and in the spring debris  can pile up on the Mills Glacier from large, heat caused  sluffs and this slope is large enough to do some damage if a slab did form and release.


lambslide couloir rocky mountain national park colorado

(Click on photo above to enlarge)


The Lambslide Couloir is the permanent icefield named after the 19th century descent by the Reverend Elkanah J. Lamb who after summiting Longs via the Keyhole, descended the Notch Couloir then Lambslide solo,  tumbling to the base only to survive and become a guide on the mountain. 

This ice slope makes a gash directly below the east face of Longs Peak on its way down to the Mills Glacier.  Potentially loaded with dangerous avalanche conditions in the winter or after big snows, a spring ascent of this classic couloir is a “must-do” on the list of any Colorado ski mountaineer.

lambslide couloir colorado backcountry skiing climbinglife guidesTracks from a mid- June descent of the Lambslide with Eric Sparks.  

Ideally one can skin all the way up from the car;  otherwise, a walk in shoes then a switch to skis and skins can be the trick in later season.  Our June 14th ascent in these photos gave us perfect corn ski in the couloir only wearing our ski boots from the east end of Chasm Lake and tennies from the parking lot to the lake.  There was enough ice on the lake to safely ski across on the way up and then quickly down on the descent of the Lambslide.

Approaching the Lambslide Couloir is typically done  by hiking or skiing to Chasm Lk. via the Longs Peak Trailhead (3.7 miles).  Skiing and climbing directly up the Couloir from Chasm Lk to the top cab be a 1-2 hr. climb depending on snow conditions and fitness.

This hidden slope can also be accessed from the top by climbing to the Loft (saddle between Mt. Meeker and Longs Peak) from it’s east side and then easily traversing into and dropping in from above. 

There is often avalanche danger in this terrain so no ascent or descent should be done without the adequate preparations.

I generally prefer the bottom-up approach as it allows one to assess and locate the best skiing conditions on this slope before committing to a descent.

climbing the Lambslide Couloir, Longs Peak Colorado

(Click on photos below to enlarge)

 lambslide couloir eric sparks longs peak colorado lambslide couloir longs peak colorado

Chasm Lake and the final approach to the Lambslide Couloir– putting down tracks in the steepest section near the top. 

The average angle of the Lambslide is around 40 degrees with some steeper and less steep sections.  Of course this is the perfect angle for slab and loose-snow avalanches and so considerable care must be taken in the decision-making process.  Late spring conditions and early winter conditions tend to be the best and if the ice is in shape, ice climbing could be combined with a ski descent.

The top of the Couloir offers a great prepping spot for the descent with incredible views of the nearby Diamond face of Longs as well as down to Chasm Lake and across the Front Range.  When the snow is good, there are few descents in Rocky Mountain National Park that rival the Lambslide.

lambslide couloir longs peak colorado ski mountaineering

By late summer in most years, the Lambslide can become a cascade of falling rocks and black glacial ice as the snow of winter melts down to the base layers of ice and embedded stone. At that point in time, crampons and ice screws are necessary as well as a cold night and early start to avoid problems.  Until then, skis are the recommended mode of travel in this ultra-classic ski couloir.


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