The northern part of the San Rafael Swell is stunningly beautiful. Unfortunately the crumbly layers of sandstone from which this splendor arises are frighteningly bad from a rock climbers perspective. Holds can't be trusted and protection is marginal at best. However, those souls who brave the choss are rewarded with especially mind blowing vantages of the surrounding incredibleness. Dom and I have really grown fond of this place.
Nearly 20 miles of dirt road separate Assembly Hall Peak from I-70. The San Rafael River flows less than a mile to the north and impressive formations like Window Blind and Bottleneck Peaks keep it company. The summit can be reached via a two pitch route known as Heavy Metal [5.10 C0] that was put up by James and Franziska Garrett in 1992. The climbing is not exactly enjoyable but the views along the way are otherworldly. Despite its relatively low stature compared with its neighbors, Assembly Hall is one of the more difficult peaks to get on top of in the area.
The approach from the San Rafael Bridge Campground requires less than 1,000 feet of elevation gain spread over about a mile and offers stunning views in and of itself. Assembly Hall's massive north facing amphitheater, for which I'd imagine the peak is named, is a very natural and inviting line.
The only difficulty along the approach is one minor cliff band up high which is equipped with an old fixed rope. If this line disappears or becomes unusable a couple of partner assists should get the job done.
Hiking up the gut of the bowl delivers one to a difficult 30 foot cliff band and the first technical pitch of the route. An obvious 5.10- crack in a left facing corner is the most attractive weakness, though a couple other crack systems also look reasonable. Comfortable hand jams lead to fists and eventually awkward offwidth near the top. Cams #2 to #4 get the job done. After worming your way onto the low angle slab above the crack scramble up and left to a bomber two bolt anchor.
A few hundred feet of straightforward scrambling lead to the second and final pitch located on the far west side of the headwall above the amphitheater. This pitch up a chossy seam is the business, and is much longer and more serious than the first. Slabby, sandy, insecure climbing on piss poor rock leads to the first bolt 30 feet up. There are a few very marginal placements along the way, but the leader would have to get very lucky for any of them to hold a fall and keep them off the deck. I took a fall while following when the slightly upraised dimple that I was delicately using for my hand disintegrated. The situation would have been very ugly if I'd been on lead. I don't know how Dom has the head for this stuff! I'm pretty sure I was more relieved than he was when he reached that first bolt!
Upon reaching the first bolt the climb becomes much less nerve wracking. Closely spaced bolts in good condition give the option of easy C0 aiding (no aid gear needed) if you so choose. Traditionally this is how the climb has been done, though chossmaster Dominic saw no reason not to freeclimb the whole thing, using the bolts only for protection. First ascensionist James Garrett reports that he also freed the route on a return trip.
The bolt line traverses continually left where you are finally presented with a near perfect hand sized cam placement. Place the piece and move sharply to the right up easy but loose ground until you hit scrambling terrain. Due to the sharp turn in the line you'll almost certainly be dealing with some rope drag and want to set a gear anchor soon. The rappel anchor you'll be using on the descent is further to climbers right and isn't convenient for belaying on the way up. The roomy summit plateau is just a short scramble away.
But wait! A close look at the topo suggests that the tiny point to the south of the main summit plateau is actually higher by one 40 foot contour. And unfortunately a large notch separates the two.
Fortunately, a clean crack in the northern summit and a few hand sized cams make for a bomber rappel anchor...
The climb out of the notch to reach the southern highpoint looks a bit discouraging from the northern summit, but is actually quite reasonable despite its steepness, thanks in part to handy handjams right where you need them. The more conservative climber or those averse to jamming may appreciate cams in the 0.75 to #2 range.
As expected, the summit views are top notch in every direction. Window Blind is the highest thing around for miles and certainly looks the part. Sort of ironic since climbing Assembly Hall felt like Window Blind on steroids to me!
I've read about a 5.8ish upclimb to regain the northern summit and it does look reasonable as a toprope, but very loose. Since we had ascenders along we chose to jug back up the overhang directly above the notch instead.
The descent from the large northern summit mesa is straightforward, though reaching the three bolt top anchor is somewhat spicy. A belay wouldn't be a terrible idea here as its quite loose. We cleaned the frayed mess that was serving as anchor material and replaced it with shiny new webbing. Although the line looks loose from the top, it becomes nice and clean once over the edge.
