REI Community
Ypsilon Mountain
Select Route:
Blitzen Face T 
Blitzen Ridge T 
Prancer Ridge T 
Y Couloir (Left Branch) 
Y Couloir (Right Branch) T 

Y Couloir (Left Branch) 

YDS: 5.0 French: 2- Ewbanks: 4 UIAA: I ZA: 6 British: MM 1c X

Type:  Alpine, 1500', Grade IV
Original:  YDS: 5.0 French: 2- Ewbanks: 4 UIAA: I ZA: 6 British: MM 1c X [details]
FA: unknown
Page Views: 4,703
Submitted By: Willie Mein on Jun 9, 2003

You & This Route  |  Other Opinions (7)
Your todo list:
Your stars:
Your rating: -none- [change]
Your ticklist: [add new tick]
Your opinion of this PAGE:    [0 people like this page.]
Left Branch of Ypsilon's Y-Couloir, late June ...

Seasonal Closures MORE INFO >>>


This is one of the most spectacular ski descents in RMNP.

Although this is a climbing site and many people think of the Y couloirs as snow/ice/mixed climbs, the left Y Couloir (climber's left, skier's right) is most remarkable as a ski mountaineering adventure.

Typically the best time to catch this East-facing couloir is in the early morning, in the early spring. One can either approach from the Lawn Lake trailhead (below), or from the Alpine Visitor Center (above). The complete tour, starting from Trail Ridge Road/Alpine Visitor Center and coming out at the Lawn Lake Trailhead is an awesome ski mountaineering experience; however, it is dependent on the opening of TR road. The approach from below is straightforward and allows one to assess the conditions before dropping in on skis.

A single alpine axe and crampons should suffice for ascending the couloir. Many climbers may feel comfortable without a rope.

With many miles, a lot of vertical, high summits, insane exposure, and wicked skiing, this is a very big day under the best circumstances.


Self arrest.

Photos of Y Couloir (Left Branch) Slideshow Add Photo
Rock Climbing Photo: The Y Couloir the approach trail on 7/7/02. You ca...
BETA PHOTO: The Y Couloir the approach trail on 7/7/02. You ca...
Rock Climbing Photo: High above Ypsilon Lake in the Left Branch.
High above Ypsilon Lake in the Left Branch.

Comments on Y Couloir (Left Branch) Add Comment
Show which comments
By Willie Mein
Jun 10, 2003

The top of this couloir is barely visible in this photo.Conditions were rough on 6/9/03, with very little snow below treeline. There was a very prominent (6'x6') runnel that ran the length of the couloir and there is still a huge cornice at the top. The SW face of Yipsilon looked good, and would have been a better ski.Although I didn't see anybody all day, I did have cellular reception from TR road to the Lawn Lake trailhead.
By George Bell
From: Boulder, CO
Jun 10, 2003

Curious, how can "very little snow below timberline" translate into "rough conditions". I would think no snow would make the approach easiest!

In my experience it's best to wait until July for the Y-Couloirs, as their cornices fall down by then ...
By George Bell
From: Boulder, CO
Jun 10, 2003

Duh, I get it now, you were skiing! I imagine this always involves lots of walking as the Lawn Lake trailhead is so low ...
By Willie Mein
Jun 10, 2003

Exactly. Also, down low, where there was any snow, it was patchy and not continuous enough to ski. On foot, I was postholing. Threcher conditions for some of the approach and descent. I came in from above (from Trail Ridge) and nearly found myself stuck wallowing in poor conditions from the start. I must have taken my skis on and off at least twenty times throughout the day. For skiing, go early spring. For climbing, wait a little longer till the cornices drop. For a good workout, go now.
By Brian Story
May 4, 2007

This is one of the best ski runs I've found in the front range. Snow on the approach is always thin, so plan on some hiking regardless of the season. This line can be skied mid-winter with stable conditions which makes the approach/egress a little easier. Cornice danger is an issue. The fastest way to gain the couloir is to climb snowfields on the south face.
By Mike Brown
May 29, 2009

Please let me know when someone gets a look at the left arm. I have a climb planned for early July 09. Any condition report would be helpful.
Thanks so much.
By Scott Matz
From: Loveland, CO
Jun 26, 2009

I have plans for tomorrow up the left branch I will leave a condition report. If any one wants to team-up for an early start, email me @
By Ryan Marsters
Jun 20, 2016

The exit cornices haven't dropped, but they've melted out quite a bit and are fairly stable. The sun hits the left branch exit cornice around 8AM. Smaller cornices left of the Left Branch exit could still drop and funnel into the main coulouir/runnels (a few up to 8 ft deep).

We hit one melted patch of scree about 20-ft long 3/4 of the way up. Otherwise, awesome icy snow and AI (mid-foot to front points) up to 60 deg, perhaps short steps of 70-80 deg depending on how one crosses the runnels - a second tool was handy.

I enjoyed Left Branch far more than Right Branch w/ 5.4 bypass in late June conditions. R may be better when the ice is in, which seems to be before the cornices stabilize or drop.

Mountain Project

The Definitive Climbing Resource

MTB Project

Next Generation MTB Trail Maps

Powder Project

Backcountry Ski Maps & Secret Stashes
FREE Stickers · Gyms · RSS · School of Rock · Contact · About