Buckner Mountain Theodolite Survey, Lick of Flame W Face FA, Horseshoe Peak

Buckner Mountain (9,112 ft) Theodolite Survey, Lick of Flame (8,400ft) First Ascent via West Face, Horseshoe Peak (8,480ft)

Oct 1, 2022, 1am – 10pm

21 miles, 8,200ft gain

Eric, Steven, Talon

Summary of results: Buckner SW summit is 18.9 +/-3.5 inches taller than NE summit.

Buckner Mountain was my final Bulger peak back in 2018 and I’ve been very intersted in it recently. The mountain has two peaks of nearly equal height and up until now, in my view, they have not been surveyed carefully enough to definitively determine which is the highest of the two peaks. This is significant for many reasons. People climbing the Bulgers want to be certain they climbed the correct peak. County highpointers want to know so they can visit the true highpoint of Skagit County. And, in general, since Buckner is one of the few 9,000 footers in Washington it is great to know exactly where its summit is.

I’m aware of four previous measurements taken on Buckner. In 2018 Greg Slayden and Jobe Wymore took Sokia 5x sight levels up and estimated the SW 1-2 ft higher. These levels did not give angular measurements so no error bounds were given. My own experience with Sokia 5x sight levels is that at 600ft distance the vertical error is around +/- 2ft. In 2018 Greg Slayden used photo analysis code written by Edward Earl of pictures taken from one peak looking at the other to estimate the SW peak was between 9.6 in and 27.8 in taller. The code relies on multiple atmospheric and weather-related correction factors for photo distortion, and as far as I’ve heard the model has yet to be validated. So I’m not comfortable trusting this result yet. No error bounds are available for this measurement.

In September 2022 I took a more accurate Sokia 5x sight level up capable of measuring angular declination/inclination with a resolution of 0.2 deg. I took measurements from each summit looking at the other and determined the height difference was within the resolution of the sight level. That means they were within about 2ft of height, but I couldn’t tell which was higher. In 2022 a LiDAR survey was conducted of the area which measured the SW summit was 17 inches taller than the NE. However, according to my friend who is a LiDAR expert for his job, the error bound in this measurement is high enough that it doesn’t definitively determine which peak is higher. In general, LiDAR doesn’t do great with pointy peaks like Buckner because the sampling can easily miss the true summit, adding to error.

My interpretation of all these measurements is that the potential error is too high for each measurement, meaning it’s not clear which peak is the true summit. A measurement needs to be taken where the potential error is less than the height difference, meaning even if the measurement has the highest possible error it still gives the same result of which peak is higher.

I’m aware of two possible solutions. A high-end dual frequency survey-grade GNSS unit placed on a peak for at least an hour can theoretically get 1-inch vertical accuracy. I’ve used these before, surveying peaks in west Africa and Saudi Arabia, but I don’t currently have access to one and they are expensive to rent or buy. Alternatively, a theodolite can be used to very accurately measure angular declination or inclination. High-end electronic theodolites can get 1 arcsecond angular resolution but are very expensive. However, old-fashioned mechanical theodolites are relatively cheap and can still get 20 arcsecond angular resolution. This would be more than sufficient to figure out which peak was the true summit. Plus, batteries don’t run out on a mechanical unit.

I had never used a theodolite before, but I’m a mechanical engineer and it sounded like a fun tool to figure out. Apparantly surveyors in India still use mechanical theodolites, since I found the cheapest theodolites online on ebay all ship from India. I justified buying one since it’s an interesting problem to figure out and I can think of a handful of other peaks that would benefit from a super-accurate ground survey that I could then conduct.

The unit finally arrived in late September, but I was worried it would snow in the mountains and I would miss my last chance to get an accurate measurement this year. Luckily, though, this fall has been exceptionally dry and the summits were still predicted to be snow free into early October. I first needed to learn how to use the theodolite, though. I found tons of useful information online, and it is a simple enough device that it wasn’t a problem. The Vernier scale it uses in an ingenious way to get a very accurate measurement purely mechanically.

I spent a few days taking measurements outside my apartment. To check the calibration of the vernier dials I got a 48-inch measuring stick and mounted it on a tree, then took angular measurements from 50-100ft away sighting the top and bottom. I measured the horizontal distance to the stick with a Bosch laser range finder with 1/32″ accuracy and calculated the height at 47.9 inches, which was very accurate given I might not have mounted the stick perfectly vertically. This satisfied me that the unit was in good working order.

I planned to go and take the Buckner measurements Saturday October 1. Talon and Steven were interested in joining. They are working on Bulgers and they both needed Buckner and Horseshoe, another Bulger nearby. I had already been in the area twice to climb Buckner and Horseshoe, and I kind of wanted to throw in another objective in case there was time for a bonus point. I knew Buckner and Horseshoe wouldn’t take all day, even with the surveying.

There is one other peak, Lick of Flame, that is between Buckner and Horseshoe and was intriguing to me. It is an extremely sharp spire, and from the correct vantage point it does indeed look like a big flame coming off the ridge. I was intrigued because, as far as I’ve researched, it has only been climbed once. This was by Silas Wild and Russ Kroeker in 1982 via the 2-pitch 5.8 east face. I looked back through some of my old pictures and it looked to me like a potential line up the unclimbed west face. This sounded like a fun challenge to try to put up a new route up an unclimbed face up a very remote peak.

So the plan was we would haul in my 25 pounds of survey gear (theolodite + fancy tripod + big padded carrying case + miscellaneous smalller measurement devices), then a 60m rope and a single rack. With three people we could distribute the load. This trip would thus have quite a few objectives with uncertain timing (taking theolodite measurements and climbing an unclimbed route), so we wanted to leave early. The plan was to start at 1am at Cascade Pass trailhead, then make it to Buckner shortly after sunrise. That ought to give us time to then climb Lick of Flame in the middle of the day when the temperature was warmest, then tag Horseshoe hopefully before sunset. Getting home super late was ok, since the next day was still the weekend.

Friday evening I drove to Cascade Pass and made it to sleep shortly after sunset. Talon and Steven arrived later and I don’t think they got too much sleep. We were all up and moving by 1am with me carrying the survey equipment in my big 100L pack and Steven and Talon splitting the climbing gear.

We made good time up to Cascade Pass and then up to Sahale Camp, passing two girls on the way who were planning to get up Sahale by sunrise. The trail ended at Sahale Camp but I was very familiar with the route, having done it twice, including just a few weeks earlier.

I navigated us down around the snowfield so we didn’t have to wear crampons, and then on to the rock rib. It was a

bit harder navigating in the dark, but we made it no problem. We carefully descended the ridge, and I had to take my time downclimbing the steep bits with my monster pack and tripod sticking out. We then descended the loose gully and made it to Horseshoe Basin.

There we gained the standard ledge at 6600ft and traversed to the old abandoned mine. The sun finally started coming up as we passed the mine. We did a gradually rising traverse on the steep scree and talus, and eventually reached the snowfield at the base of the Lick of Flame. It was tempting to start up the Lick of Flame then, but my priority for the trip was the Buckner survey. So we ditched our climbing gear at the snowfield, then I gave Steven the tripod to carry and we continued up.

More snow had melted since I had been here in early September, and that meant more choss scrambling. We carefully made our way up the very loose southwest slope, then did the final scramble up to the southwest summit. We then started executing the survey.

My plan was to take ten independent measurements, then average them all and find the standard deviation to get the most accurate result possible with error bounds. The first set of measurements would be vertical angular measurements from the SW summit looking to the NE summit. The theodolite has two different vertical vernier discs for two different angle measurements, then standard practice is to rotate the horizontal base and the sighting piece each by 180 degrees and take two more measurements. This way any slight inaccuracies in the leveling of the

device on the tripod can be averaged out. I would then take a transit survey. Talon would hold the 48-inch measuring stick on the NE summit and I would set the theodolite to be perfectly horizontal. Then I would see where the horizontal cross hairs intersect on the measuring stick. I would then hike all the equipment over to the NE summit and repeat all the measurements looking towards the SW summit. So that would be ten independent measurements, each of which by itself should be capable of determining which peak is higher and by how much.

The potential sources of error would be the angular resolution (20 arcseconds), the measurement of the height of the theodolite above the summit it is mounted above (error 1/32″ with my laser range finder), error in distance between the summits (based on google earth I estimate this is 600ft +/- 10ft), and error in leveling the theodolite (though this should be averaged away by taking the four different angular measurements in each direction).

I started setting up the tripod on the SW summit while Talon scrambled over to the NE summit. We each had radios to coordinate, and Steven was the photographer. It was actually kind of precarious setting up the equipment since there are cliffs on both sides of the SW summit block. But the tripod legs are long enough that I was able to get it solidly set up exactly over the summit. I verified this by hanging the plumb bob underneath on a string. I then carefully opened the pelican case and took out the theodolite, then securely affixed it to the tripod.

The theolodite has two buble levels and three tuning discs to get it

perfectly horizontal. As I’d practiced at home, I got it perfectly level in one orientation, then rotated it 90 degrees horizontal and made fine adjustments. I continued this procedure all the way around until it was perfectly level. This procedure was very precarious as I was balancing above the cliff on all sides of the tripod.

I then adjusted the sighting cross the be centered exactly on the NE summit. Unfortunately, despite the weather forecast being mostly sunny, some pesky low clouds were rolling in between the summits. But luckily they went in and out enough that I could get a clear view of the top. I then took zoomed in pictures of the vernier scale reading on the C and D disks. I planned to later look at the pictures to take the measurements, since zooming in on the pictures would give the most accurate readings.

I then rotated the horizontal disk and sighting scope 180 degrees and redid the measurements. Next, I radioed Talon, who had by then made it to the NE summit. He held the measuring stick vertically on the NE summit and I set the sighting scope to be 0 degrees, so perfectly horizontal. With the 30x magnification I could just about read the writing on the measuring stick, but not quite. For this sighting the cross hairs hit a bit above the top of the measuring stick. So I had Talon extend a measuring tape above the stick. I had him move his finger up the measuring tape until it perfectly aligned with the cross hairs, and then I told him to stop and read out the measurement. I could resolve about a half-finger width with my scope, so this measurement would be accurate to within about 1/2 inch.

That was the last measurement from the SW summit, so I radioed Talon that we would switch positions and repeat. I packed up the theodolite and Steven strapped on the tripod. Talon made it back over as we were packing down, and he rested on the SW summit.

We then started the scramble over. It looks intimidating but is just 3rd class. We followed the ridge crest over the first hump, then dropped onto the right face and scrambled around some gendarms on good ledges. Then we regained the ridgecrest and scrambled to the NE summit.

This summit is less precarious, with only one side exposed. The summit boulder pile was much wider and I could much more easily mount the tripod. I again leveled the theodolite on the tripod, verified with the plumb bob that I was exactly over the summit, and started taking measurements. Like before I took four angular measurements, then did a transit survey.

This time I could direclty sight the measuring stick in the cross hairs. I had Talon move his finger up the measuring stick until it exactly matched the horizontal cross hairs in my sighting scope, then he radioed me the measurement. I then rotated the horizontal disc and sighting scope each 180 degrees and repeated the measurements.

I would need to process the results at home from the angular measurements, but the transit surveys were showing the SW summit between 14-22 inches taller. The error was likely from the theodolite not being perfectly level. Still, to be absolutely certain I wanted to analyze all the measurements. [Note: after analyzing all measurements at home I concluded the SW summit is 18.9 inches taller with one sigma error +/- 3.5 inches]. We packed back up and scrambled back to the SW summit by 11am. There was plenty of time left in the day, and we were excited to tag on our next two objectives.

It seemed kind of weird that climbing a new technical route on Lick of Flame would just be the secondary objective for the day, but we were trying to get our full value out of our time in the Buckner zone.

We descended the chossy southwest face carefully, then traversed back to our climbing gear. We put harnesses on, then traversed the snowfield to the base of the Lick of Flame. We briefly admired the East Face, and indeed it looked like plenty of cracks and a good route went up. But we weren’t interested in the east face this time.

We countinued kicking steps across the south side, then reached the base of the gully coming down from the west face. There we ditched the survey equipment at a rock outcrop and put on rock shoes. The gully was loose scree but we scrambled up third class rock on the left side until reaching the notch in the ridge connecting to the Boston Glacier to the north. From the notch we scrambled west up a small knob to get a view of the route.

The route was a up-left trending open book that went almost to the south ridge before connecting to another corner up and left. Above that was a small ledge and a crack system leading up the west face to the summit. The lower half of the route looked low-angle with featured rock, but it was unclear if there were cracks for gear. We couldn’t see the upper part of the route, but saw a few good cracks in between for a potential first anchor.

We agreed the route would probably go, and Talon volunteered to take the first pitch. He had brought a 60m x 8mm rope and would tie in to the middle and belay us up on the trailing ends. I belayed him up from the chilly, windy gully just below the notch. He surmounted a small overhang on the bottom, then got up to a ledge. Above that he managed to get occasional gear in, before reaching the planned achor point just at the end of the rope.

He got in a good anchor in the crack system and belayed us both up. There were generally bountiful small positive holds for feet and hands, and we rated the pitch a fun 5.6. I volunteered for the next lead. This was now up a corner with a south face on the left and overhang on the right. I made some fun hand and foot jams, and found lots of gear options. At the top of the face I found a huge ledge and decided to belay from there. I’d rate that pitch 5.7.

Steven volunteered for the last lead. This was great since we would each get to lead a pitch. He climbed straight up the west face from the ledge, surmounting one tricky slightly overhanging section that we agreed was 5.8. Then he reached the summit and slung the summit for the belay anchor.

Talon and I followed and we all balanced on the small summit at the same time. The route had no rap anchors, had loose rocks inside some cracks, and had moss and dirt in some cracks. There was no evidence it had ever been climbed before, so it is very likely a first ascent.

We hung out taking pictures for a little while, then planned our retreat. We slung some webbing around the summit, put in a rap ring, and backed it up with a cam. I rapped first, and made it all the way down to the lowest anchor point. Talon and Steven followed as I built the next anchor. I pulled out some dirt and loose rocks to sling another horn, and we pounded in a piton next to it in a separate crack for good measure. The last rappel brought us back to our starting point, and we scrambled back to our gear.

It felt like we had already accomplished quite a lot that day, but we still had Horseshoe as our last objective. This time we tried to traverse at the top of the snowfield on rock. Steven scrambled up a sketchy section that I wasn’t comfortable soloing with my monster pack full of survey gear. So he and Talon dropped my a rope to get over that.

From there we scrambled up to the ridge east of Horseshoe, then followed a ledge across to gain the base of the standard climb. We ditched extra gear there, then Talon soloed up to the summit. I was happy to have the rope since I remembered the last move on the top was slightly overhanging with crappy rock and exposure. Steven belayed me up the ledge trending up and left. I got a few cams in then pulled over the lip and reached the summit.

I then belayed Steven up and we all enjoyed our fourth and final summit for the day. Talon even found a summit register and signed us in. We hadn’t found one on Buckner. I guess it had been kind of full when I was up there in September so maybe someone had brought it back to the mountaineers. It’s kind of disappointing they didn’t replace it though.

The sun was getting low and the views were great from Horseshoe. We still had a long ways out, though, so we took turns rapping down. We then picked up our ditched gear and descended back to the base of the snowfield. From there we followed our same route out, descending the chossy slope down to the right, then following the ledge back across Horseshoe Basin. We scrambled up the rock rib and made it to Sahale Camp just in time for sunset. We then made a fast hike back down the trail to the trailhead around 10pm. I scarfed down some snacks and drove home by 1:30am.

Results from survey:

After analyzing all measurements at home I concluded the SW summit is 18.9 inches taller with one sigma error +/- 3.5 inches.

Here is a link to a google doc spreadsheet of my raw measurements and my calculations: https://docs.google.com/spreadsheets/d/11m0DzDz5F3m4rtgjYWflSAkm_u1V_bzDRNTT29J5pvE/edit?usp=sharing

The data from the SW looking towards NE had a higher standard deviation so more error. This was likely because it was very precarious to get the theodolite perfectly level there. I had to be balancing above a cliff on two sides to do it, so wasn’t quite as careful. From NE looking to SW was much less precarious and I got it much more level. This is shown in the much lower standard deviations in the measurements. So I’m quoting the average and standard deviation from all the six measurements from NE looking towards SW. That is the most accurate. But if you look at all the data or just SW looking towards NE it’s still pretty similar. All the data is in the google spreadsheet if anyone is interested in going through it. I also have the pictures of each angular measurement if anyone wants to look at those.

I closed a very simple level loop that went from SW summit to NE summit then back to SW summit. I got a closure error of 6.99 inches. The acceptable closure error of 1/5000* horizontal distance would be 1/5000*600ft*12 in/ft *2 = 2.88 inches (I put that in my spreadsheet also). I suspect the higher error was from the theodolite not being as level on the SW summit as I would have liked. That was tricky because of the exposure. I bet a professional surveyor could get much less error. I’m definitely an amature. But my interpretation is the error is still small enough to not have any effect on the conclusion that the SW summit is higher, which is what most people care about anyways.

If you want to support gas money for future surveys you can click the button below. (I’m just doing these surveys for fun, not part of any job and not paid.)

 

 

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