[Eric Gilbertson]

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.

On the NE summit of Buckner with the theodolite (photo by Steven)

The route

Detailed route

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.

My 5x sight level on Buckner in September 2022

Testing the theodolite at home

Hiking up Sahale Arm

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.

Traversing below the snowfield near Sahale Camp

Hiking above the old mine

Looking across towards the ptarmigan traverse

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.

Horseshoe Basin at sunrise

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.

Scrambling up the talus

Hiking up the SW slope

Nearing the SW summit, with Booker in the background

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 setup on the SW summit

Taking measurements (photo by Steven)

Looking at Talon on the NE summit through the scope

The measurement plan. I measured d, h, theta, w and calculated z, the height difference

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.

Radioing to Talon to coordinate (photo by Steven)

Packing up and leaving the SW summit

Nice views towards Boston and Forbidden

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.

Scrambling to the NE summit

Setting up on the NE summit

Taking measurements from the NE 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.

Looking at the SW summit through the cross hairs with 30x magnification

The view of the SW summit with no magnification

Steven on the NE summit

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.

Panorama from the NE summit

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.

The team (photo by Steven)

Heading towards the Lick of Flame

Traversing around the south side

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.

Our route up the west face

Talon leading the first pitch (photo by Steven)

Climbing up to the first anchor

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.

Me leading pitch 2 (photo by Steven)

Steven and Talon following pitch 2

Steven leading the last pitch

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.

On the summit

View of Boston Glacier, with a new fire starting in Thunder Creek

Rapping down (photo by Steven)

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.

Approaching Horseshoe (photo by Steven)

On the summit of Horseshoe

Talon on 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.

Last view of Lick of Flame (left) and Buckner (right)

Crossing Horseshoe Basin

Sunset from Sahale Camp

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. Link to more pictures

[GaliWalker]

This comment is meant to be in jest... So how do you know that your tripod height was identical for both summits? What a fun read! Such a lot of content.

[Bruce Albert]

Fascinating undertaking. I’m struggling a bit with your conclusion (but not disagreeing with it). Did you close a level loop, and what was the error in closure? From what I recall, 1/5000 horizontal distance was the acceptable closure error for third order work. After about two setups with a tribrach and optical plummet, few would ever use the plumb bob again.

[Stefan]

Now that is impressive. It sounds like you came very close to what LIDAR information says.....even though LIDAR may be off. If you are coming to the same conclusions....

[Roald]

This is beyond cool. Makes me consider learning how to use some of these tools. Congratulations, and thanks for the info and description.

[Eric Gilbertson]

[Eric]

Thanks for the effort to re-do Buckner twice (!) this year in the interest of determining which summit is highest. Your conclusion makes me especially appreciative as someone who did only the SW summit since it confirms no need to go back, though I imagine I'll be in the area sometime for Booker at least. I am sure there are many other Bulger climbers and other peakbaggers who are gratefully for your work too!

[GaliWalker]

[SeanSullivan86]

Cool. Snoqualmie Mountain and Guye Peak could use this treatment. Are you willing to speculate about which of these summits on Buckner is at more risk of losing height soon? Also, any ambiguity about detached blocks at the summit influencing the height? You mentioned a "boulder pile".

[Eric Gilbertson]

[Bruce Albert]

Thank you for posting your data and your methods. I have just a couple of more thoughts: I think your results confirm which is the higher of the two summits, and I applaud the work you went to to do the research. I also think the results are a lot less conclusive as to just how much the height difference is. I think there's clearly an issue with your 'precarious' setup on the SW summit, because of the large variation in your results. In land surveying it was pretty standard to turn angles twice - then reconciled in software - but the software also rejected shots where the difference between shot one and shot two exceeded a preset value. A large difference between values which should be equivalent screams that something is funky; it is not enough to take the mean and drive on.. I haven't climbed Buckner, but is it possible there is a good instrument setup location a short distance from the summit to which one could transfer an HI and proceed? Being an engineer, not a surveyor, are you familiar with instrument technique, e.g. one hand only on the instrument with the lightest touch possible? A two handed grip or firmly grasping manner is apt to really raise hell. Feel free to restrain your self on decimal precision. 0.01 ft being just under an eighth of an inch more digits to the right of the decimal are just overkill. Your trig leveling method relies for accuracy on a horizontal distance not measured or (apparently) verified. It may be entirely accurate or it may not. People get into trouble with this all the time looking at assessor's aerial photos, thinking they are accurate to show property lines when in fact there are these massive parallax distortions. And yes, with the tangent of very little being almost nothing it would take a significant error in horizontal or slope distance to really blow the result out of the water. A lightweight target, just a square with contrasting quadrants capable of sliding up and down whatever you're using as a rod would make shots at that distance easier to make with greater accuracy. And lastly, a project like yours begs for a total station and a good prism. Good used units are available for reasonable $$$ and the weight isn't really that much more. If you've an interest in other such research projects I bet you'd be glad you picked one up. Anyhow, hoping you don't feel sniped at by all this; I thought it was really cool how sort of started from scratch and did all that.

[scottk]

Now that we have the answer everyone likes, people should stop researching this question. Furthermore, everyone should start adding rocks to the SW summit.

[Bruce Albert]