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The Slab
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$00pr kr33m S 
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YDS: 5.2 French: 3 Ewbanks: 8 UIAA: II ZA: 8 British: D 2c R

Type:  Trad
Consensus:  YDS: 5.2 French: 3 Ewbanks: 8 UIAA: II ZA: 8 British: D 2c [details]
FA: Unknown
Page Views: 2,140
Submitted By: George Bell on Apr 11, 2002

You & This Route  |  Other Opinions (23)
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Mark Oveson a hundred feet up Diagonal, The Slab (...
Climbing areas reopened after flood MORE INFO >>>


This is one of the longest routes near Boulder, especially if you go all the way to the summit of the Slab. However, much of it is 3rd or 4th class.

Begin at the far right side of the slab. This is the only place where the approach trail passes within a few feet of the base of The Slab. A few hundred feet up you can see a wild wing-like flake jutting out over the northeast arete.

The route goes up the the east face, staying within 100' of the northeast arete. Near the wing-like flake, the easiest option is to follow a ramp left until you can get over a steep section. It is also possible to climb closer to the arete, or even go under the wing-like flake (5.5).

Once you reach the ridgecrest between the east and west faces, the climbing becomes much easier. Follow this crest for quite a distance (many pitches if roped). You will pass a gnarled tree marking the end of the routes "Left 'N Up" and "Syzygy". Beyond this follow a narrow arete past a troublesome tree and make a scary step down while hanging off great holds on the crest. Right after this, look for the downclimb to the west, look for a wild flake sticking out that you lower over and step onto (despite appearances, the flake is quite solid). Alternatively, climb 20' farther and then down a dead tree leaning up against the west face (not recommended, as the tree is deteriorating).

The summit actually lies many pitches farther. If you wish to reach it, follow the ridge until it ends in hiking terrain (however, The Slab itself is a continuous piece or rock below and east of you). Hike up and left, and get into a weird gully that diagonals left below a headwall. Climb through this headwall with a short 5.0 move, then wander up to the thumb-like summit. This summit can be reached either from the east (exposed 5.2) or west (4th class), and has a great view of the Devil's Thumb and Sphinx to the south. This summit is higher than The Goose.


Standard Flatiron rack.

Photos of Diagonal Slideshow Add Photo
Summit ridge - note the dead 'descent tree' in center of photo.
BETA PHOTO: Summit ridge - note the dead 'descent tree' in cen...
Summit ridge pools.
Summit ridge pools.
George Bell on the north end of the summit ridge on The Slab, Flatirons South.  Above my head are Pellaea and Onoclea.  To the right is the Fiddlehead and East Ridge.  Photo by Mark Oveson.
George Bell on the north end of the summit ridge o...
Summit ridge.
Summit ridge.
Mark Oveson about halfway up the summit ridge on The Slab.  The rock in the background is The Goose.
Mark Oveson about halfway up the summit ridge on T...
The downclimb is just after this bump.
BETA PHOTO: The downclimb is just after this bump.
Looking north.
Looking north.
Long ways up.
Long ways up.
Lots of greenery.
Lots of greenery.
Bolted rap anchor behind this tree.
Bolted rap anchor behind this tree.
Much lichen.
Much lichen.
Sea monkeys! The summit ridge pools contained tiny silvery shrimp.
Sea monkeys! The summit ridge pools contained tiny...
Another view north.
Another view north.
Downclimb. Looks harder than it is; there are good edges.
BETA PHOTO: Downclimb. Looks harder than it is; ther...
Comments on Diagonal Add Comment
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By George Bell
From: Boulder, CO
Jun 10, 2002

Note that the "troublesome tree" mentioned in my description is the green pine tree in front of the dead tree (lower portion out of photo can be used for descent) in this Photo.

Also, be aware that the downclimb with the scary flake is probably the hardest move on the route.

By Scott Conner
From: Lyons, CO
May 16, 2003

Great description, George. We did this route as an after-work scramble this week. Excellent rock, long climb. We continued on to the true summit. The climbing becomes discontinuous and dirty but the summit block is cool.

To descend from the summit, contour around the west side of the Slab to the north, then east until you gain the base of the climb.

By Brandon Bogardus
From: Scottsdale, AZ
Mar 28, 2006

Good god, DO NOT solo this route when there is still a substantial amount of snow on the ground. You'll be climbing up a wet slab, only to be faced with snow, ice and water on the ridge traverse. Trust me, I know - I'm the idiot that found this out the hard way today. If you see me on the street, please smack me for being stupid. Thanks.

By Wayne
From: Superior, CO
Jul 12, 2008

Forget downclimbing the dead tree. The stubs from the branches stick out like daggers, and the lower part looked pretty rotten.

By Aaron Martinuzzi
Dec 22, 2009

Though the route goes through a lot of hiking terrain, it is worth making a trip to the summit of the slab - it's a nice little spire with an airy, but easy, 15' of climbing to reach the top. A downclimb, probably 5.0, can be had on the north side of the west face. No need to bring a rope up this rock.

Mar 28, 2011

Didn't descend either tree - both looked horrible. Just climb to the summit - there is a little bit of a downclimb, but we did it in approach shoes - then just walk off.

By fossana
From: Bishop, CA
May 26, 2012

After the dead tree and before the summit, there is a ramp. If you drop down here, you will find a vegetated but easy downclimb near a corner system (see beta photo).