Blackcap Mountain Survey – New WA Top 100 Peak

Blackcap Mountain Survey – New WA Top 100 Peak

July 7, 2023

32 miles, 3:30am – 12:30am

Summary of results: Elevation 8,402.4ft +/- 0.1ft, Key col elevation 7,996.2ft +/- 0.1ft (NGVD29 datum), Prominence 406.2ft +/-0.2ft. New WA Top 100 peak.

I’m continuing to determine the true WA top 100 peaks through very accurate ground surveys of edge cases that can’t be determined by the quads alone. Next on my list was Blackcap Mountain.

Blackcap Mountain is a Bulger peak, and this will never change. But it was thought to have a prominence of only 397ft and thus did not qualify for the true WA top 100 highest peaks list. A peak needs at least 400ft of prominence for inclusion and needs to be of sufficient height.

Blackcap is in the interesting situation where it has not yet been measured by Lidar. It seems Lidar coverage of the Pasayten and the North Cascades is not currently a high priority for this. The summit of Blackcap was directly surveyed on the quad as having an elevation 8,397ft. The key col that determines prominence is the col connecting Blackcap to Monument Peak. This col was not directly surveyed, but is shown as approximately at the 8000ft contour on the quad.

If the saddle was just a little below the 8000ft contour then that could make the prominence greater than 400ft. Also, if the summit elevation were a little higher, the prominence could also be greater than 400ft. In my experience comparing Lidar surveyed summits to quad surveyed summits I’ve found it’s not uncommon for there to be a difference of a few feet.

Thus, I considered Blackcap Mountain a close enough edge case that a ground survey would be needed to definitively determine whether it qualified as a WA top 100 peak.

As with previous peaks I’d surveyed for prominence, I thought this one would likely be tricky to measure with a theodolite. Also, the theodolite is pretty heavy to lug in there for a 32 mile round trip hike. I decided to bring in my differential GPS unit. I would take a one-hour measurement at the saddle and a one hour measurement at the summit.

It would be easy to find the summit, but perhaps a bit trickier to find the saddle. I’d previously been to the summit but not to the saddle, and I couldn’t find any reports of anyone going to that saddle. From pictures I’d taken previously it looked like it was potentially 5^th class to access, and there were a few candidate low points on the ridge that could be the true saddle. I needed to find the lowest to take my measurements.

I was going in solo and decided to take a 30m rope and a bit of rock pro in case I needed to rope solo the climb up to the saddle. I didn’t want to get all the way in there and be turned around by a 5^th class climb.

I decided to take the Monument Creek approach since this was slightly shorter than starting from Slate Pass. The main disadvantage of the Monument Creek approach was the Eureka Creek crossing. On a previous trip I’d needed to packraft across this since the bridge had long ago been washed away. It has proved a very difficult ford/swim for other hikers in recent years. Luckily, though, my friend Ross had been in there a few weeks earlier and confirmed a bridge had just been constructed over the crossing. So I could leave the packraft at home.

Thursday night I drove in to the Monument Creek trailhead, arriving by midnight. I took a nap for a few hours then was up and moving by 3:30am. The first 3.5 miles were flat and went by very quickly in the dark. It was light out by the time I reached the shiny new bridge, and Eureka Creek was no longer a problem. The trail crew that made that bridge did a great job!

The trail beyond the bridge used to be in tough shape, but it has been mostly logged out now. I made fast time up the switchbacks to the crest of the ridge. After a few miles the bushes had taken over the trail and there were occasional blowdowns. I lost the trail at one point and continued cross country, but then refound it.

From there the trail was in excellent shape. I traversed below Pistol Peaks and soon reached Pistol Pass. From there I got a great view of Lake Mountain, Monument Peak, and Blackcap Mountain in the distance.

I planned to take the most direct way to Blackcap, which was to climb up and over Lake Mountain. I dropped down the trail a few switchbacks then bushwhacked straight across to Lake of the Woods. That would be a really good campsite, and I’d camped there on a previous late-October ascent of Lake Mountain in a lot of snow.

I filled up water at the lake, then scrambled up the standard east face/ridge route to the summit of Lake Mountain by 10am. I signed in then continued along the north ridge. I soon had to drop on the west face and traverse below some cliffs, but then followed the ridge proper.

After crossing a lot of boulder fields I reached the critical gully just east of Pt 7688 to drop off the ridge. I had anticipated this to be snow-filled based on satellite images, but it was mostly melted down to choss. It looked like my aluminum crampons would not be needed, but I kept them on my pack just in case.

The gully was quite steep and chossy, and I knocked a lot of rocks down. It would definitely have been more pleasant if snow filled. I finally reached the bottom, then traversed across talus fields until I reached a grassy meadow with running water.

There I filled up and got my first good view of the Monument-Blackcap ridge. There were two locations that each might possibly be the col, but it was impossible to tell for sure by eye. I laid down and took out my 5x sight level and it appeared the north saddle was lower than the south. But it was hard to be certain from that distance and not being exactly in the middle of them.

I hiked up the grassy meadow as far as possible, then hiked up talus to near the base of the cliff leading to the ridge. It looked like basically all routes to access the ridge were 5^th class. I was prepared for that with my rope and rack, but it would be much faster if I could find a nontechnical route up.

I started on the north side and walked all the way south along the ridge until I was a bit past the south saddle. There it looked like I finally found what might be a scramble route, but it was unclear if it would go. I switched in to rock shoes, put on my harness, and ditched my extra gear at the base at a snowfield.

There I started scrambling up. It was steep, but I found a 4^th class way up and eventually reached the ridge crest. The ridge was very narrow but fun. I followed it north, at times scooting along au cheval, and at times traversing just below the crest.

I soon reached the south saddle and tried to determine if it was the lowest. This would be a straightforward measurement with two summits, but not with two saddles. Luckily the ridge curved a little. I scrambled down the west side so my eyes were level with the south saddle then pointed the sight level over towards the north saddle. My scope was clearly level with a point above and behind the north saddle. Thus, the north saddle was lower and was the key col for Blackcap.

I continued scrambling along the ridge, then dropped down into the steep and narrow notch of the col. The skies were getting dark by then and I saw rain in the distance, so I tried to move quickly. I mounted the GPS antenna a little outside the notch to get a better view of the sky, and measured the height of the antenna above the bottom of the notch with my tape measure. Then I started logging data.

I also took out my two sight levels and measured angular inclination angles up to the summit, which appeared to be just visible from the saddle. As I was doing this the storm got closer and it eventually started raining. The wind picked up and I heard rumbles of thunder.

I really wanted to get the full one-hour measurement, but also didn’t want to get stuck up there in a thunderstorm. At the bare minimum I needed at least 20 minutes of data for it to be processed by OPUS. I waited nervously and took a bunch of pictures. After 20 minutes the wind started picking up and it was thundering more. I held out until the 30-minute mark and then had to call it. In theory that would still get at least 4 inch accuracy, which I hoped would be sufficient.

I quickly packed up my gear. By now the lichen on the rocks were wet and slippery and I didn’t want to scramble all the way back along the exposed ridge in the wind and rain. I had the rope and rack, so I decided to go directly down as quickly as possible.

I scrambled down some blocky rocks until I hit the edge of the cliff. Unfortunately my 30m rope would not reach down the whole way. But I recalled a ledge going partway up from the ground a bit farther south. I carefully scrambled south until I saw what I thought was the ledge.

Luckily just above it was a small tree/bush that felt solid. I wrapped the rope around, weighted it, then rapped down. It just barely reached the ledge. From there I pulled the rope and scrambled delicately back down. It felt great to be off the technical terrain.

I walked back south to pick up my stashed gear and switched back into my trail runners. The skies were still dark but the rain and wind had died down a bit. I contemplated bailing and hiking out, but I didn’t think I had enough measurements to definitively determine if Blackcap qualified or not. I might get the saddle measurement to the nearest inch, but I couldn’t be sure the summit elevation from the quad didn’t have a few feet of error. I really needed to get the summit elevation measured accurately also.

The summit was only class 2/3, so shouldn’t be a problem even in the rain. My GPS antenna and rover unit were nominally waterproof, so I figured I could be very careful and still get a good measurement.

I hiked over talus to the base of the normal scramble route and ditched my climbing gear there in a trash bag. I scrambled directly up to the north ridge, then followed the ridge to the summit.

By then it was drizzling and kind of windy, but tolerable to get the important measurement. Luckily the thunder had stopped. I set up the antenna tripod next to the highest solid rock and measured the height of the antenna above the rock with my tape measure and sight level. Then I started logging data.

I whipped out my 5x and 1x sight levels but the saddle wasn’t exactly visible from the true summit. However, if I walked a bit along the ridge I could see the saddle area. I used my sight level and tape measure to measure how high the true summit was above the highest rock where I could see the saddle area. I would have to add this height to my sight level-determined height for the final result. The sight level measurement would only be to increase confidence in the much more accurate GPS result.

Unfortunately it was impossible to confidently point the sight levels exactly at the saddle, even with 5x magnification. The rocks around the saddle looked too similar and the notch was small enough that I couldn’t be sure exactly where it was. At least I had some measurements from the notch up to the summit.

The drizzle came and went, but I was able to keep the rover unit dry inside its padded travel case. I killed time taking pictures and looking through the summit register, which was completely full.

Finally the end of the hour came, just as the rain and wind picked up again. I quickly saved the data, packed up, and headed down by 4:15pm. It was kind of late in the day already, and it would have been nice to camp out at the base of the peak, but I needed to make it all the way out that evening.

I scrambled down the wet rocks in the rain to my stashed gear, then packed up and continued down. I was a bit nervous about taking my exact morning route back out. It looked like more thunderstorms could come in and they could easily catch me above treeline on Lake Mountain. I had kind of wanted to get a really good measurement of the elevaation of Lake Mountain, but that was just a bonus measurement and not required since Lake Mountain is solidly on the WA top 100 list.

I decided to instead stay low and bushwhack around to Lake of the Woods to meet up with my morning route. I had previously done part of this route on another trip and was pretty confident it would work.

I dropped down into the trees, then traversed below the cliffs. I crossed two notches en route and got pretty wet pushing through the bushes, but I was happy to not be worried about thunderstorms.

At the last notch the mosquitos got really bad, and this is one of the few times I’ve ever had trouble with bugs in Washington. I guess I’m rarely here in the summer like this, though.

I soon made it to Lake of the Woods and saw two hikers camped on the opposite side. I waved but didn’t stop to talk. I was  hoping to make it back to Seattle that night and still had a long ways to go.

I made it to the trail and then started cruising. The hike up to Pistol Pass went quickly, then I cruised all the way back down to Eureka Creek. Finally by 12:30am I reached the truck.

This time I didn’t really have any obligation in town the next day so didn’t see a need to pull an all-nighter driving back. So I just took a nap in the truck for a few hours before heading back to town in the early morning.

Back in Seattle I waited the necessary 24 hours after the measurements were taken, then uploaded the data to OPUS, the NOAA online processing tool for surveyors. I found the summit elevation was 8,402.4ft +/- 0.1ft and the key col elevation was 7996.2ft +/- 0.1ft (NGVD29 datum, same as used by the quad). This means the prominence is 406.2ft +/-0.2ft. The prominence is above 400ft, meaning Blackcap Mountain is officially on the true WA top 100 list.

Interestingly, it appears that the col is a bit lower than shown on the quad and the summit a bit higher than surveyed on the quad. These two small errors were just enough to bump the prominence over 400ft.

As a double check, I also calculated the prominence based on my sight level measurements. I found this resulted in a prominence between 405ft-409ft. There are higher error bounds on this measurement based on how well I lined the bubble up in the sight levels, but the result is consistent with the GPS measurement that the  prominence is greater than 400ft. Thus, I’m confident reporting that Blackcap Mountain is now a WA top 100 peak.

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.)

 

© 2023, egilbert@alum.mit.edu. All rights reserved.