The Thumb

I’d heard about the thumb from Kristine who’d been considering some obscene linkup of the Thumb, Birch Mountain, and/or Mt Bolton Brown. In early June I’d seen that Jim, JD, and Kristine had managed a linkup of Birch and Bolton Brown (though Jim did not make it to the latter summit) and I talked to Jim about the current conditions. He mentioned that he’d done a 5,000 ft glissade down Birch and that conditions on The Thumb looked even better, so I was sold. I managed to enlist Chris as well, cautioning him that it could be well over 2,000 ft of hiking before we hit the snowline.

I arrived a day early planning to hike Birch, but due to some unforeseen laziness and the comfort of my new truck camper I put some modest effort into trip reports instead. Chris arrived Monday night, just before eight and we watched the sun set on the sierra before packing our bags for the approaching long hike.

We woke at 4:30 am for a 5 o’clock start and managed to hit the trail almost on time. We followed the forest service road past the area where we’d parked and it quickly dissolved into the meadow. Suddenly we were surrounded by gorgeous irises which kept my mood high despite my wet feet.

We lost the road completely but managed to eventually find our way to the trail thanks to the maps on our phones. As the sun came up behind us we were treated to a light show as the early morning alpenglow hit Mt Tinnemaha and Birch Mountain above us, eventually flooding McMurray Meadows and Owens Valley below with light.

The use trail climbed steeply through a dry ravine before becoming more defined and switching back along the north side of Birch Creek. Above us, we saw no evidence of snow and realized that we might have to hike 5,000 ft for 2,000 ft of skiing, rather than the other way around!

We passed through various wildflowers along the way, noticing yellow flowers adorning the northeast slopes and lush purple lupine flooding the southeast slopes. Despite heavy packs and a long way to go, we kept a decent pace, arriving at a saddle below Kid Mountain around 10,000 ft just after 7:30 am.

Finally we had a glimpse of snow above us, although it was still mostly avoidable. Eventually the trail disappeared into a long stretch of snow and we were forced to boot across it. Luckily the snow was soft enough that we were able to get decent grip in our trailrunners without needing to stop and put on crampons or ski boots. Nor was the snow steep enough that either of us bothered swapping our poles for an ice axe.

Although we were frequently forced to abandon the trail where snow overran it, we were able to follow its course fairly easily until we hit a dense patch of willows with no indication of a trail. We scrambled through the dense thicket for a while before coming to a gushing spring with a narrow snowbridge. Chris didn’t want to risk walking across the snow bridge and I thought that it was obvious that this would be a good place to put skis on and take a snow route up to Birch Lake. I descended twenty feet to where the snow appeared more solid and put on my skis and boots while Chris climbed upwards a dozen feet and scrambled across to solid rock.

He shouted back to let me know there was a route, but I was already in my boots so I decided to forge ahead. My right ski punched through the snow in a weak spot as I tried to cross but I managed to keep my balance and avoid dunking my ski in the spring. The traverse was annoying and I was eventually forced to take off my skis to climb the rock up to Birch Lake in my ski boots. I found Chris on the north side of the outlet of Birch Lake and sat down in a shady spot nearby.

We had some lunch while letting our wet socks and trailrunners dry in the sun. Looking across Birch Lake, we unanimously agreed that it was a bad idea to cross the lake. Even though there was only a small amount of open water at its outlet, the ice was blue with melt water; even if the ice was thick enough to support us, our skins would get saturated with water during the crossing. We examined the slope above the lake and had some debate as to the best route. My map very distinctly indicated that the south slope was the shallowest, so that got my vote while Chris thought it looked too steep and wanted to climb the west slope.

We opted to circumnavigate the lake along the south, climbing the south slope if it looked feasible or continuing to the west slope if not. Before leaving, I stashed my snow pants, ski jacket, and trailrunners, as it was far too warm to wear the former and I would have no need for the latter. As it turned out the south slope was not as steep as it appeared and made for easy climbing in our skis. Reaching the top of the slope, we found that the rocks were starting to melt through the snow in many places, complicating the route. With some minor maneuvering we found our way through the bowl.

Above us, several steep couloirs ran down the northeast face of Ed Lane Peak — I would love to come ski them some day! As we were forced to cross thin patches of rock, Chris shouted back to me to let me know that he’d noticed some minor collapsing of the snow. I wasn’t too concerned as the snow near rocks is often non-uniformly heated and can cause funky weak layers to form, but it was good to know.

Now that we had a view of the ramp, I was becoming concerned that during our climb out of the bowl to the summit plateau of The Thumb we might break through such a weak layer or a glide crack and fall deep inside the snowpack. I mentioned this to Chris and told him that although it might be steep skinning, I’d rather skin up the ramp than boot, since it would afford us greater buoyancy and lower likelihood of an unexpected posthole. Chris, always more comfortable on rock than snow, pointed out the cliff to the right and suggested that we might find an easy route up it.

As we neared the ramp, we noticed a narrow couloir splitting the cliff to the right which looked like fun skiing. Unfortunately it looked like a little too much fun to be having 7 miles and 6,000 ft from the trailhead! We also had a better view of the ramp and indeed, there were some large glide cracks forming at the base of the ramp on either side. With the amount of ski penetration we were seeing, I was really skeptical that the snow would be supportable enough to safely boot across a buried glide crack, so we decided to try to find a route onto the cliff to the right.

With some minor difficulty we made our way onto the cliff, stowing our skis on our pack and starting the ski boot scramble. I led the way up the cliff, which would have been easy class 3 climbing in trailrunners but was quite a bit clumsier in ski boots. At one point my foot slipped and I put my toe into the rock wall with enough force to break it had I not been wearing ski boots! Then again, if I weren’t wearing ski boots it probably would not have hit so hard… My helmet tumbled out of the helmet carry on my backpack, bouncing once on the rock before hitting the snow below and sliding a few hundred feet before coming to rest. Luckily it wouldn’t be far out of the way on the descent!

We made our way to the top of the cliff without further incident and carefully found a route onto the snow, booting fifty feet to a shallower slope before putting our skis back on and skinning up the plateau toward the summit. A beautiful layer of inch deep corn adorned the slope and I was already excited for the descent! The summit reared up above us to our right and several smaller buttresses lined the slope to the left, giving the feeling of being in the palm of a giant — perhaps this is how the peak got its name!

We were able to skin within a hundred feet of the summit before the snow let up. We stashed our skis and scrambled up to the top.

The views from the summit were sublime! We were spitting distance from Middle Palisade whose severe east ridge rose another 1,000 ft above us! There was almost a skiable line from the summit, too!

I was excited for this new perspective on the Palisades as well as my closest view yet of Split Mountain which was still holing a surprising amount of snow on its north slope!

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We had another snack atop the peak, taking in the views and signing the register. We didn’t linger long, partially because I could feel that the sun was already starting to bake my skin and was eager to get out of the solar oven that is the snowy high sierra and partially because it was nearing 12:30 pm and we knew that the snowpack would begin to rapidly warm and destabilize.

We climbed back down to our skis and began the descent. I skied the first pitch down to a patch of rocks and shouted up to Chris, letting him know that the corn snow was phenomenal (in case he hadn’t heard my hollers of joy)! He followed me and continued along the fall line toward the bottom of the plateau.

After Chris passed me, I started a traverse towards the “fingers” of the bowl, thinking that the southeast aspect looked slightly steeper and more fun.

I don’t know that it ended up being a better line than Chris’s but it wasn’t too much extra effort and it was truly glorious skiing! Soon I joined Chris near the top of the ramp.

Because of the heat of the sun and late hour, we were cautious in how we wanted to ski the ramp which would be the steepest section of the route. We agreed that we should stay in visual contact as much as possible and that we should ski cut the slope before starting the descent. We creeped nearer the top of the ramp before realizing that it wouldn’t be possible to have eyes on the first skier without the second skier being on the same slope. Chris opted to go first, and to avoid putting us at risk of being buried in the same avalanche, I stayed higher up on a lower angle slope above some rocks which should anchor the snowpack. We agreed that he would ski first and I would follow after a 40 second count, hoping to give him enough time to get off the slope before I descended, but little enough time that I’d be able to watch him if he were caught. We didn’t think the risk of avalanche was very high, but since we’d opted to go without beacons for the day, it would be essential that we could see the other if an avalanche occurred.

Chris started toward the ramp, putting his weight heavy into his skis as he cut the top of the slope. The snow was wet and there was a lot of ski penetration but the slope held. He let started down the slope and I counted the seconds in my head. After five seconds I heard him shout “SLIDE!” I quickly descended to where he’d begun his ski cut hoping to get eyes on him and immediately found him skiing on the far right side of the ramp as a wet slab made slow progress down the center of the ramp.

I found a safe place to stand above another rock anchor and made sure that he was out of the path of the avalanche. After confirming that he was okay and that he felt safe, we watched as the slab made it slow, churning path to rest at the bottom of the ramp. Since there was not much snow left to slide on the ramp, I made a severe ski cut into the head of the avalanche to try to understand what was going on. Only when I was five feet from the edge of the avalanche path was I able to trigger the slope. I stopped on the bed surface and had a look at the avalanche (observations at bottom).

I skied the bed surface down to Chris. It wasn’t great skiing, but by skiing in the path of the avalanche I was confident that I was very unlikely to trigger a second slide. Before continuing on I made sure Chris was in a good headspace. He remarked that this was his first avalanche but didn’t seem rattled in the least. We were now very glad that we’d decided not to climb this slope!

We collected my helmet a few hundred feet below before continuing the rest of the way to Birch Lake, taking turns leading the route down the relatively low angle slopes and navigating around the complex moraines. As we descended, the snow became softer and more rotten, our skis penetrating more than 6 inches into the snowpack and making skiing somewhat challenging. As we approached the last pitch to the lake, we began to let off a serious amount of sluff. I shouted to Chris to wait up so we could see if the sluff would build into a wet loose slide, but it didn’t end up entraining any more snow. Soon we were back at the lake and traversing back towards my stashed gear.

Chris wanted to return to the outlet of the lake to get some more water. I was feeling quite sun-baked and opted to continue along a more direct route. I found a snow route through the moraine and ditched my skis to take shelter in the shade of a large boulder. Chris had said he’d climb back to me up the moraine, but after five minutes I heard him shout and descended to figure out what was going on. He’d opted instead to continue descending and traverse back onto my route.

Rather than retrace our climb down the north side of the canyon, we decided to ski as far down the snowier south side as possible before returning to the the trail. For the most part the descent was uninteresting, comprising much traversing through shallow suncups and avalanche debris. Rocky buttresses rose up above us on the north flank of Birch Mountain. Nearing the snowline we were rewarded with three pitches over nearly 1,000 ft of surprisingly decent spring skiing!

We’d managed to get an extra 1,500 ft of skiing on the way down, but now as we crossed Birch Creek it was time for some cross country hiking back to the trail.

We switched back from ski boots to trailrunners and I hastily stowed my ice axe on my pack, putting Chris in charge of making sure it didn’t fall off (my skis obstructed the normal mounting point). We hiked southeast toward the trail, climbing slightly through a desiccated and long-burnt forest. Chris led for a while before having sympathy on my unprotected legs (I always prefer to wear shorts) and allowing me to take the lead.

We soon found ourselves on a rapid descent toward the trail. Along the way, we found a surprising amount of garbage including a newish pair of sunglasses and some long rusted metal. Arriving back at the trail, I asked Chris if my ice axe was still on my pack — it wasn’t! Luckily, he’d been following me to the top of the descent so we knew it couldn’t be more than 100 ft uphill. There must be something about this slope that makes everyone drop their gear… Unfortunately, my GPS had stopped recording though, so I had no way of accurately retracing my steps. Chris’s GPS was still recording so we left our packs on the trail and started uphill, following Chris’s track and finding the axe about halfway up. It seems like loosing an axe is surprisingly common!

I secured my axe to my pack a little more carefully and we made a rapid descent back to the trailhead, finishing off the final 2,500 ft in less than 90 minutes. We arrived at our cars at 4:30 and took a leisurely shower and dinner break, hitting the road shortly before sunset.

I was interested to follow Chris’s route out but accidentally took a wrong turn which led me through 3 miles of paint scraping chaparral before ending at a deep creek crossing, requiring me to make another 3 mile trip through the screeching sage brush.

I found the turn I’d missed and was surprised that he was able to make the trip up and down some severely rutted roads in his outback. Soon I was back on Route 395 and off to the next adventure!

Trailhead Discussion

Google will choose the shortest route regardless of hazards, so I highly encourage doing research on the forest service roads. I have created the following color coded map based on my observations from this trip. Markers and lines color coded:

• Red: 4WD, High Clearance Required
• Orange: AWD, Moderate to High Clearance Required
• Yellow: AWD Maybe Required
• Green: Passable by all vehicles

Snow Discussion

Avalanche Forecast

https://www.esavalanche.org/content/avalanche-advisory-sunday-apr-21-2019

Snow Observations

• Slight whumpfing near snow/rock interfaces
  • No propagation
• Very warm snowpack
• Corn snow on plateau
• 3-6 inches ski penetration below plateau on east aspects

Avalanche Observations

Sadly due to miscommunication between me and Chris, we did not report this observations to ESAC in a reasonable timeline, but here is the data, nonetheless:

• Location: 37.0665, -118.4405
• Date: June 11, 2019 1:30 pm
• Red Flags
  • Whumpfing
  • Rapid warming
  • Obvious avalanche path
• Avalanche Details
  • Skier triggered
  • Elevation: 12,200 ft
  • Aspect: SSE
  • Slope Angle: 27 degrees
  • Above treeline
  • Slab Layer: likely partially consolidated storm slab (four finger hard)
  • Weak Layer: unknown
  • Bed Surface: likely old suncrust (pencil hard)
  • Crown Height: 8 inches
  • Avalanche Width: 60 ft
  • Avalanche Length: 150 ft
  • No complete nor partial burials
• Weather Details
  • No wind
  • No cloud cover
  • 55+F (estimated) and warming
  • No precipitation

GPS Data

Elevation Gain: 7,500 ft