Mt Formidable Survey

Mt Formidable Survey

Oct 1, 2023

21 miles, 7,000ft gain, 5am – 11pm

Summary of Results: Summit elevation 8352.9ft +/-1.1ft

I’m continuing to survey peaks in Washington to determine the most accurate possible list of WA Top 100 peaks. There are a handful of peaks remaining that have been directly surveyed on the quad, but have not been surveyed by Lidar or with a differential GPS unit and are still within error bounds of list inclusion. In general a differntial GPS survey gives the most accurate elevation, followed by Lidar, then by a directly surveyed point on the quad. I’ve found in a few rare cases the quad-surveyed elevation of peaks can be off by up to 30 ft compared to Lidar. These peaks are Sherpa, Clark, and Raven Ridge (interestingly, the quad has underestimated each of these). Thus, any peak in this situation within 30ft of the cutoff for list inclusion could potentially be bumped off the list or added to the list.

In my most up-to-date list of the top 100 (found here and kept up to date: https://docs.google.com/spreadsheets/d/1gYaBTa32bLfXiQFrcpTJ58KjO1HIAEEMBDrttHFxUOg/edit?usp=sharing) Formidable has been number 100 at 8325ft. Thus any peak with only a quad-surveyed elevation of 8295ft – 8355ft is within the error bounds for list inclusion. Currently these edge-case peaks are Apex, Andrew, Castle, Luna, Big Snagtooth, Cosho, Windy, Austera, and Snowfield.

I’m prioritizing surveying the peaks closest to the border of inclusion, and Mt Formidable was the closest at number 100. If the quad elevation was over in error by just 2 ft Formidable could get bumped off the list. But in the other direction it could get bumped up and be more solidly on the list. So I planned to bring the differential GPS unit to the summit to measure the elevation.

Josh was interested in joining. I had just surveyed Katsuk Peak Saturday with Colin, and that took a little longer than expected. After getting back to Easy Pass I drove immediately to Cascade River Road and met Josh at the MP 16.5 hairpin at 11:30pm. Our plan was to climb Formidable car to car via Drop Creek. I had previously climbed Formidable in late september 2017 from Cascade Pass and had descended Drop Creek, so I was mostly familiar with the route. However, that time Matthew and I hadn’t realized there was an abandoned trail through Box Canyon. We’d bushwhacked along the west side and had to simul-climb across some cliffs.

I told Ryan about this trip and he later climbed up and down the drop creek route and reported there was actually a decent trail most of the way. Josh and I decided to take this route for Formidable since it avoided the sketchy late-season glacier conditions on the Middle Cascade Glacier that would be required if approaching via the Ptarmigan Traverse.

Based on conditions on Katsuk Saturday I expected up to a foot of snow higher on the route on Formidable. In fact, when I climbed it with Matthew in late September 2017 there was also a foot of snow on the route. There is one exposed class 3/4 ledge traverse above a chasm that we simul climbed that time. So this time I brought a 30m rope and pro for that section.

On Sunday morning we were moving by 5am. The trail must see some unofficial maintenance since it’s in very good shape for an abandoned trail. I suppose the main destinations are to hike to the base of the Middle Cascade Glacier and to the South Cascade Glacier. We passed the intersection to the Middle Cascade Glacier and then the trail went very close to the south fork river. Based on my previous hike out of Formidable I recalled walking long stretches right along the banks of the river. So in the dark, not seeing any flagging anywhere, we started following the river.

This went well for a while, but then we were forced to bushwhack a few times. Luckily I had loaded Ryan’s GPS track and noticed the trail was not, in fact, along the river bank. We bushwhacked back in the dark and eventually found it. From then on we were very diligent to follow the flagging and signs of the trail. It got much easier once the sun rose. Some creek crossings are tricky finding the trail on the other side, but in general it’s in good shape. I can report the east side of Box Canyon is indeed way easier than the west side.

We eventually reached Drop Creek and crossed on a huge log. On the other side we left the trail and followed the creek. The forest was mostly very open as I remembered, and the bushwhacking went smoothly. By 10am we popped out in the basin below Mt Formidable and got some amazing views. The meadows were covered in frozen due, the blueberry bushes were bright red, and the summits were covered in snow. It was very colorful.

We hugged the right side of the alder patches and scrambled up talus. At the head of the basin we hiked up steep heather slopes, then cut left to get around a few cliffs. At the edge of the snow and the top of the heather we saw an orange bivy sack set up. That would have been an amazing place to spend the night! Above the bivy sack we followed the footprints of the owner, and that made navigation very easy.

At 7600ft we hit the base of a snowfield and crossed to the base of the summit cliffs. There we saw the other climber descending. I joked to Josh there was a 50-50 chance we would recognize the other climber. That seems to be happening a lot lately to me. Sure enough, it was Ross hiking down. He yelled my name just a hair before I could yell his name. He had the awesome bivy and had just soloed the climb. He said he just has 13 Bulgers left now!

We chatted a bit then continued up. It was very fun scrambling on melted-out rock, and then we got to the deeper snow on the exposed ledge. It seemed slippery and sketchy to me, especially with the heavy pack carrying the pelican case and survey gear. We had the rope so we decided to use it. I built an anchor and Josh belayed me around the corner. The 30m rope was the perfect length. At the end I slung a horn and belayed Josh. He left the cams in so I could sport lead back across.

I recalled that was the only sketchy section so we left the rope there. We continued up on partially snow-covered ledges. It was class 3 but sort of tricky in a few places. By just before 3pm we finally reached the summit. I think carrying the survey gear and climbing gear had slowed our pace a bit.

I verified with the sight level which rock poking up was the highpoint, then mounted the GPS antenna tripod on it. There was a bunch of snow and I packed that around the tripod legs. I started logging data and then we rested and took pictures. After 20 minutes, though, I noticed the antenna rod was starting to tilt a bit and was no longer vertical. It appeared the black tripod legs had heated up in the sun and melted the snow supporting them. I really should have supported them on rocks but wasn’t thinking. I’d never had this issue before, so I just delicatly tilted the antenna back to vertical and packed the snow more solidly.

After anothe 20 minutes it sagged a little again. This time I just left it until the full 1hr measurement was completed. By 4pm we packed up and headed back down. We carefully downclimbed back to the chasm, then pitched out the traverse. We then downclimbed back to the snowfield. The fresh snow was now slushy enough that it slide off down to ice below. Luckily we’d brought crampons and made it down fine.

We retraced our route back to the woods, and were bushwhacking down Drop Creek by sunset. We soon reached the trail, then followed that back to the trailhead by 11pm. We noticed what looked like fresh broken window glass on the ground next to our cars. Luckily our cars hadn’t been broken into, but one of the other two cars parked there probably was (I hope it wasn’t Ross’s car!). I made it home by 2:30am, in time for a few hours sleep before my 7:45am Statics lecture.

At home I tried processing the data with OPUS but it gave me errors. It appears the tripod melting and tilting the tripod added just enough error that OPUS wouldn’t process it. I knew the first 15 minutes the antenna was perfectly vertical, though. So I spent a few days learning exactly how to read the raw measurement data in a text file (a RINEX file). I figured out how to crop it so it was only the first 15 minutes. OPUS was able to process this data. This gave me a final elevation of 8352.9ft +/-1.1ft. The 1.1 ft error is higher than usual, but this is likely because it is from only a 15 min measurement. This is the minimum measurement OPUS will process, and the errors usually get exponentially better over time.

Interestingly, this means Mt Formidable is actually 27ft taller than the quad-surveyed height. This is very similar to the cases of Sherpa, Clark, and Raven Ridge. This means Mt Formidable is no longer number 100 on the list and is bumped farther up (currently number 91). Big Kangaroo and Mt St Helens are currently tied for number 100 at 8326ft.

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