The Lidar/dGPS Washington Top 100 List

The Lidar/dGPS Washington Top 100 List

Eric Gilbertson, Kyle Bretherton

Aug 2017 – Oct 2024

Summary

All peaks and contender peaks in WA for the Top 100 list have now been surveyed by either Lidar, dGPS, or both. It is now known exactly which 100 peaks are on the list. All double summit disputes have been resolved with theodolite, sight level, Lidar, dGPS, or a combination of these.

Significant changes from the Quad-based WA Top 100 list to the Lidar/dGPS WA Top 100 list:

-East Fury, Solitude, Chalangin, Blac

kcap added
-Sherman removed since prominence less than 400ft
-Luna, Switchback, St Helens removed
-Order changed based on updated elevations
-Rainier summit has changed location (lilkely around 2014, from Columbia Crest to SW Rim, since Columbia Crest melted down 21.8ft)
-Eldorado summit changed location from icecap to rock (likely around 2020, since icecap has melted down 20ft)
-East Fury summit changed location from icecap to rock (likely in early 2000s or 1990s, since icecap melted down 30ft)
-Liberty Cap icecap melted down 26.3 ft. Summit location unchanged, but elevation/prominence have changed.
-Cardinal true summit is actually 5th class spire south of traditional summit, measured taller with theodolite survey
-St Helens has been losing elevation from erosion at a rate 4in/year since 1989 and left the T100 list around 2021
-Double summit cases have been resolved for Cardinal, Katsuk, Sherpa, Enchantment, Greenwood, Buckner, Buck, Copper, Big Craggy

Link to Lidar/dGPS WA Top 100 List: https://tinyurl.com/ysdvvrbm

Introduction

Climbing the hundred highest peaks in Washington is a popular peakbagging objective, involving glacier travel, rock climbing, bushwhacking, and general adventure. The list of the hundred highest peaks was first compiled by a group of climbers calling themselves the Bulgers in 1976 after the final of the 1:24,000 quads became available. Quadrangles (called quads for short) are topographic maps put out by the US Geological Survey (USGS). By 1976 all peaks were covered by the quads, with accuracy defined by 40ft contours.

The Bulgers generally chose the hundred highest list to include the hundred highest peaks with at least 400ft of prominence as determined by the quads. Prominence is a measure of how high a mountain rises above a saddle connecting it to a higher peak. Defining a prominence cutoff ensures minor bumps along a ridge don’t count as separate peaks. A peak must stick out enough on its own to be considered. According to John Lixvar, the 400ft prominence rule was chosen because “The distinction looks right in the field and can be clearly determined from maps with 40, 80 and 100 foot contour intervals.” (see http://www.rhinoclimbs.com/bulgers.html)

There were a few exceptions to the 400ft rule, though. Seven named summits with less than 400ft of prominence based on the quads were included (Seven Fingered Jack, Sahale, Dark, Rahm, Horseshoe, Little Annapurna, and Blackcap). Volcanic subpeaks were required to have 800ft of prominence to be included. According to John Lixvar, the 800ft prominence rule was expressly formulated to not treat Liberty Cap (quad-based prominence 472ft) and Columbia Crest (the historic summit of Rainier) as separate mountains, but to still include Little Tahoma (quad-based prominence 818ft).

This had the unintended consequence of eliminating Lincoln, Colfax, and Sherman peaks from the Bulgers list, despite each having at least 400ft of prominence based on the quads.

The 800ft threshold was chosen because it is the only number greater than 472 (Liberty Cap quad-based prominence) and less than 818 (the quad-based prominence of Little Tahoma) that has 100, 40, and 80 as common denominators. The numbers 40 and 80 need to be common denominators so prominence can be accurately determined from 7.5 minute and 15 minute series quads without interpolation. 100 must be included so prominence can be determined from maps with 100 ft contours.

This list of peaks is generally referred to as the Bulgers or the Bulgers list or the Bulgers Top 100 list and is the most common list peakbaggers use to work on the Washington hundred highest peaks. But a second way to climb the Washington hundred highest peaks is to use a more rigorous definition including only the top 100 peaks with at least 400ft of prominence. This is referred to as the Washington Top 100 list. This list is not as popular because it includes Lincoln Peak, generally considered one of the most difficult peaks in Washington. But both lists are recognized by the Bulgers committee, and completers of either list are recognized at the annual Bulgers party.

The Washington Top 100 list was first compiled by John Roper and Jeff Howbert betwee 1987-2001 based on the USGS quads. (see http://www.rhinoclimbs.com/Top100xP400.htm).

As of 2024 there have been 102 climbers to complete the Bulgers List and 21 climbers to complete the traditional quad-based Washington Top 100 list.

The Bulgers List stays constant and unchanged for historical reasons. However, the Washington Top 100 list should be updated if more accurate surveys are conducted. This is how it will maintain its status as the accurate list of the 100 highest peaks in Washington with at least 400ft of prominence.

In 2018 I finished climbing the Bulger List of peaks (completer number 70), and in 2019 I finished the quad-based Washington Top 100 list (completer number 17), finishing on Lincoln Peak. I then moved on to other peakbagging objectives. But in the fall of 2022 I started looking into one of the Bulger peaks with some controversy surrounding it. Buckner Mountain has two summits, an easier SW summit that is third class and a harder 4th class NE summit. They are very similar in height, so close that it’s not really possible to tell by eye which is taller.

Most climbers stop at the SW summit since it’s the first one reached on the normal ascent route. John Roper was convinced it hadn’t been surveyed accurately enough to know for sure which was the true highpoint. I brought a little handheld 5x 10 arcminute Abney level up and determined it was too close to call based on that device’s accuracy. I really wanted to settle the controversy, so I bought a 20-arcsecond 30x mechanical theodolite and taught myself how to use it.

In October 2022 I brought the theodolite and a tripod up and did a careful survey to determine that the SW summit is 1.6ft taller than the NE summit.

This got me thinking that there might be other controversial peaks on the Washington Top 100 list. The quad only has 40ft contour intervals, which is not accurate enough to capture a difference of 1.6ft between two contender summits of the same peak. Also, not every peak was directly surveyed on the quad. If the peak has an elevation written on the quad, then it was surveyed directly by a surveyor pointing a theodolite at it. But peaks without the elevation written only have approximate elevations above the nearest 40ft contour line. If they were close to having enough height or prominence for list inclusion but had just never been surveyed, then perhaps they were actually Washington Top 100 peaks but nobody knew it.

I now had the equipment to survey just like the original USGS surveyors, so I could theoretically figure out if the existing Washington Top 100 list was accurate. If it wasn’t, I could update it to be as accurate as possible. I also had access to equipment more accurate than used in the original USGS surveys. Lidar measurements from planes were slowly being published for Washington and ready for analysis, and I was also able to use differential GPS units from Seattle University and Trimble that could give absolute elevations to the nearest inch.

My goal was to thoroughly and accurately determine the true hundred highest peaks in Washington with at least 400ft of prominence: the Washington Top 100 list. I would consider the project complete when I knew for certain exactly which 100 peaks were on the list, and exactly where the summit of each of the 100 peaks was (meaning all double summit cases would be resolved).

In the fall of 2023 I posted an updated WA Top 100 list, based on over a dozen theodolite and abney level surveys relative to quad-surveyed points, analysis of all existing Lidar data, and many dGPS ground surveys. That update can be found here: https://www.countryhighpoints.com/washington-top-100-peaks-updated-list/

I still had unfinished business though, at the end of the 2023 surveying season. Several dozen peaks had still not been measured by Lidar or dGPS. A few double summits remained unresolved, and there was uncertainty exactly which 100 peaks were on the list.

Over the summer and fall 2024 I completed the remaining dGPS surveys. Lidar measurements were published for the remaining peaks on the list and contender peaks, and Kyle and I analyzed the data.

Methodology

During summer and fall 2024 Kyle and I focused on analyzing Lidar data for the remaining peaks. Then I took dGPS ground surveys to measure peaks where Lidar data was not accurate enough. These fell into three main categories: peaks whose elevation changes over time due to erosion or icecap melting, peaks tied for elevation based on Lidar, and peaks with double summits within the error bounds of Lidar.

Lidar Analysis

I downloaded Lidar data from two sources, the Washington Lidar Portal (https://lidarportal.dnr.wa.gov/ ) and the USGS TNM database (https://apps.nationalmap.gov/downloader/). Lidar data was spread across both databases, so both were needed.

I analyzed the raw point cloud laz files using QGIS (qgis.org), a free software package.

Peaks with Changing Summit Elevations

Six peaks and contender peaks have summits that change elevation from year to year. St Helens has a summit composed of loose volcanic sediment that erodes every year. I’d previously discovered it loses on average 4 inches per year, and I took a dGPS measurement in 2023 consistent with this conclusion. I returned to remeasure it again in 2024.

Five peaks have or used to have icecap summits. This means the summit remains ice throughout the summer. These peaks are Rainier, Liberty Cap, Colfax, Eldorado, and East Fury. I took dGPS measurements on each of these peaks. For Rainier I collaborated with professional surveyors from the Land Surveyors Association of Washington to plan measurements and peer-review results. I took multiple measurements in August and September and measured four USGS monuments on the mountain to corroborate results.

For the other icecap peaks I mounted the dGPS on the highest point. If the icecap had melted enough that a rock summit was the new highpoint, I measured the elevation between the rock and icecap summits using an abney level.

Peaks tied for elevation based on Lidar

After analyzing the Lidar data, we discovered there was a three-way tie for number 100 on the list. The tie was between St Helens, East Fury, and Switchback. These peaks were the same elevation within the error bounds of Lidar.

In general Lidar measurements are accurate to within +/-0.3ft in flat open terrain (see https://www.usgs.gov/faqs/what-lidar-data-and-where-can-i-download-it ). But measurements are only taken approximately every 3-6ft horizontal spacing. So sharp summits can be missed. This means Lidar can generally just be trusted to the nearest foot or so on mountain summits. Each of these three peaks were the same elevation to the nearest foot based on Lidar. I took dGPS measurements for each of these summits. (Note: Lidar can also over -read by a few feet in snow, and can misclassify dense brush as ground, leading to over-measurements by a few feet. Brush is not a problem for any Top 100 peak summits, but snow is).

Double Summits

One double summit remained unresolved – Big Craggy. It had two possible summit locations separated by 420ft horizontal and within 0.2ft elevation difference based on Lidar. This was well-within the error bounds of Lidar, so I surveyed these with dGPS.

Measurements

All Lidar data was published in NAVD88 vertical datum. To be consistent with the historical quad-based WA Top 100 list, we converted all elevations to NGVD29 datum using NCAT (https://www.ngs.noaa.gov/NCAT/), a tool provided by NOAA.

For dGPS surveys I processed data with OPUS (https://geodesy.noaa.gov/OPUS/)and CSRS-PPP. These are free publically-available software tools for surveyors provided by the US government and Canadian government.

For the Rainier measurements, professional surveyors additionally procesed the data using WSRN, the Washington State Reference Network.

Results

All peaks and contender peaks have now been measured by Lidar, dGPS, or both. It is now known exactly which 100 peaks are on the list. All double summit cases have been resolved.

The historical icecap summit of Mount Rainier, Columbia Crest, used to be 14,410ft as measured in 1956, and 14,411ft as measured in 1988 and 1998. Columbia Crest is now 14,389.2ft +/-0.1ft. This means Columbia Crest has melted down 21.8ft since the last ground survey in 1998 and is no longer the highest point on Mt Rainier. The new summit location of Mt Rainier is now rock on the southwest rim, a distance of roughly 500ft away horizontal. The highest rock is 14,399.6ft +/-0.1ft and this is the new elevation of Mt Rainier.

Liberty cap used to be 14,117ft based on the most recent Lidar measurements from 2007. It is now 14,090.7ft +/-0.1ft. This means the summit has melted down 26.3ft since 2007. The summit is still ice, though, so has not changed location.

Colfax peak is now 9,439.9ft +/-0.1ft and is maintaining elevation within +/-2ft of the most recent Lidar surveys of 2022 and 2015. The summit is still ice and has not changed location. However, the key col for Colfax, the Colfax – Baker col, has melted down 16ft since 2022.

The historical icecap summit of Eldorado Peak used to be 8,885ft in 1950. The icecap summit is now 8,865ft. This means the icecap summit has melted down 20ft since 1950 and is no longer the highest point on the mountain. The new highpoint location is a rocky outcrop 100ft away horizontal from the icecap, at an elevation 8,873.3 ft +/-0.1ft.

The historical icecap summit of East Fury used to be 8,333ft in 1980. The icecap summit is now 8,303ft, meaning it has melted 30ft since 1980 and is no longer the highest point on the mountain. The new summit is a rock outcrop to the west 100ft away horizontal with an elevation of  8321.5ft +/-0.1ft.

Mt St Helens was measured to have the same elevation in 2024 as 2023 at 8321.1ft.

The three-way tie for number 100 was broken, with East Fury number 100 (8321.5ft), and Switchback and St Helens tied for number 101 (both at 8321.1ft).

The double summit of Big Craggy was resolved with the western summit 0.2ft taller than the eastern summit. The western summit is 8473.3ft.

Significant changes from the Quad-based WA Top 100 list to the Lidar/dGPS-based WA Top 100 list:

-East Fury, Solitude, Chalangin, Blackcap added
-Sherman removed since prominence less than 400ft
-Luna, Switchback, St Helens removed
-Order changed based on updated elevations
-Rainier summit has changed location (lilkely around 2014, from Columbia Crest to SW Rim, since Columbia Crest melted down 21.8ft)
-Eldorado summit changed location from icecap to rock (likely around 2020, since icecap has melted down 20ft)
-East Fury summit changed location from icecap to rock (likely in early 2000s, since icecap melted down 30ft)
-Liberty Cap icecap melted down 26.3 ft. Summit location unchanged, but elevation/prominence have changed.
-Cardinal true summit is actually 5th class spire south of traditional summit, measured taller with theodolite survey
-St Helens has been losing elevation from erosion at a rate 4in/year since 1989 and left the T100 list around 2021
-Double summit cases have been resolved for Cardinal, Katsuk, Sherpa, Enchantment, Greenwood, Buckner, Buck, Copper, Big Craggy

Link to Lidar/dGPS WA Top 100 List: https://tinyurl.com/ysdvvrbm

The Lidar/dGPS WA Top 100 List, with link to survey report if applicable (Lidar elevations rounded to nearest foot, dGPS elevations to the nearest 0.1ft):

Rank	Peak	Elevation NGVD29	Prominence	Method
1	Mount Rainier	14,399.6	13,209.6	Differential GPS
2	Liberty Cap	14,090.7	480.7	Differential GPS
3	Mount Adams	12,273	8,132	Lidar
4	Little Tahoma	11,136	850	Lidar
5	Mount Baker	10,773	8,837	Lidar
6	Glacier Peak	10,544	7,537	Lidar
7	Bonanza Peak	9,503	3,726	Lidar
8	Colfax Peak	9,439.9	472.9	Differential GPS
9	Mount Stuart	9,414	5,341	Lidar
10	Mount Fernow	9,241	2,808	Lidar
11	Goode Mountain	9,223	3,834	Lidar
12	Mount Shuksan	9,125	4,404	Lidar
13	Mount Buckner	9,111	3,064	Lidar
14	Mount Logan	9,097	1,518	Lidar
15	Lincoln Peak	9,096	744	Lidar
16	Mount Maude	9,077	938	Lidar
17	Jack Mountain	9,065	4,214	Lidar
18	Black Peak	8,986	3,497	Lidar
19	Mount Spickard	8,978	4,820	Lidar
20	Copper Peak	8,960	502	Lidar
21	Mount Redoubt	8,958	1,843	Lidar
22	North Gardner Mountain	8,958	4,019	Lidar
23	Dome Peak	8,921	3,079	Lidar
24	Gardner Mountain	8,897	716	Lidar
25	Silver Star Mountain	8892	2473	Lidar
26	Boston Peak	8,883	930	Lidar
27	Eldorado Peak	8873.3	2208.3	Differential GPS
28	Forbidden Peak	8839	1073	Lidar
29	Dragontail Peak	8836	1782	Lidar
30	Mesahchie Peak	8805	2299	Lidar
31	Oval Peak	8795	2730	Lidar
32	Mount Lago	8743	3280	Lidar
33	Robinson Mountain	8724	1700	Lidar
34	Colchuck Peak	8706	684	Lidar
35	Star Peak	8688	1198	Lidar
36	Remmel Mountain	8683	4327	Lidar
37	Fortress Mountain	8679	1654	Lidar
38	Katsuk Peak	8678.5	435.5	Differential GPS
39	Cannon Mountain	8652	922	Lidar
40	Kimtah Peak	8644	1119	Lidar
41	Mount Custer	8648	1314	Lidar
42	Sherpa Peak	8630	431	Lidar
43	Ptarmigan Peak	8614	904	Lidar
44	Monument Peak	8610	1106	Lidar
45	Mount Carru	8604	997	Lidar
46	Cathedral Peak	8599	1021	Lidar
47	Raven Ridge	8592	1180	Lidar
48	Cardinal Peak	8591	2094	Lidar.
49	Clark Mountain	8582	1540	Lidar
50	Osceola Peak	8579	1152	Lidar
51	Storm King	8560	659	Lidar
52	Enchantment Peak	8538	517	Lidar.
53	Buck Mountain	8534	1923	Lidar
54	Cashmere Mountain	8514	1655	Lidar
55	Reynolds Peak	8512	2043	Lidar
56	Martin Peak Holden	8504	2152	Lidar
57	Hard Mox	8501	964	Lidar
58	Klawatti Peak	8500	718	Lidar
59	Primus Peak	8497	843	Lidar
60	Big Craggy Peak	8473.3	3133.3	Differential GPS
61	Hoodoo Peak	8470	472	Lidar
62	Mount Bigelow	8468	812	Lidar
63	Dorado Needle	8466	841	Lidar
64	Lost Peak	8466	1621	Lidar
65	Argonaut Peak	8455	726	Lidar
66	Chiwawa Mountain	8453	1276	Lidar
67	Luahna Peak	8445	810	Lidar
68	Tower Mountain	8440	2904	Lidar
69	Azurite Peak	8440	1943	Lidar
70	Sinister Peak	8439	853	Lidar
71	Golden Horn	8418	1216	Lidar
72	Emerald Peak	8414	753	Lidar
73	Dumbell Mountain	8411	1316	Lidar
74	Greenwood Mountain	8408	658	Lidar
75	Solitude Peak	8402.8	414.1	Differential GPS
76	Blackcap	8402.4	406.2	Differential GPS
77	Saska Peak	8399	670	Lidar
78	Spectacle Buttes	8395	1105	Lidar
79	Pinnacle Mountain	8395	1739	Lidar
80	Easy Mox	8392	586	Lidar
81	Courtney Peak	8389	800	Lidar
82	Devore Peak	8378	1763	Lidar
83	Big Snagtooth	8374.3	622.3	Differential GPS
84	Lake Mountain	8372	834	Lidar
85	Martin Peak (Sawtooths)	8372	906	Lidar
86	Mount Ballard	8371.0	867.0	Differential GPS
87	Amphitheater Mountain	8369	807	Lidar
88	West Craggy	8367	728	Lidar
89	Austera Peak	8366	485	Lidar
90	Chalangin	8366	410	Lidar
91	McClellan Peak	8363	1247	Lidar
92	Mount Formidable	8352.9	1941.9	Differential GPS
93	Snowfield Peak	8346	2916	Lidar
94	Castle	8343.3	3263.3	Differential GPS
95	Tupshin Peak	8343	1144	Lidar
96	Windy Peak	8335.1	1807.1	Differential GPS
97	Cosho Peak	8333	517	Lidar
98	Abernathy Peak	8327	824	Lidar
99	Flora Mountain	8323	1805	Lidar
100	Mount Fury East Peak	8321.5	3113.5	Differential GPS
101	Mount Saint Helens	8321.1	4590.1	Differential GPS
101	Switchback Mountain	8321.1	471.1	Differential GPS
	Big Kangaroo	8318	1051	Lidar
	Spider Mountain	8312	970	Lidar
	Apex	8302.0	1013.0	Differential GPS
	West Fury	8298	358	Lidar
	Andrew	8293.5	1625.5	Differential GPS
	The Temple	8290	837	Lidar
	Luna	8286	1348	Lidar
	Sherman Peak	10133.0	395.0	Differential GPS

Discussion

The Lidar/dGPS WA Top 100 list is now complete, meaning it is known exactly which 100 peaks are on the list and all double summit disputes have been resolved. Thirteen peaks on the list have summit elevations measured by dGPS, and the remaining 87 peaks have summits measured by Lidar. All key cols in the US have also been measured by Lidar, dGPS, or both. (The key cols for Rainier and Baker are in British Columbia, which is not covered by Lidar, so digital elevation models are used for these cols). Peaks with elevations that change over time have had summit measurements in 2024, so are as up to date as possible.

It is possible the order of a few peaks on the list could be switched if they have not yet been measured by dGPS, only by Lidar. Any peaks within a few feet of elevation based on Lidar might switch order if surveyed by dGPS. For instance, the pairs Redoubt and North Gardner, Dorado Needle and Lost, Tower and Azurite, South Spectacle Butte and Pinnacle, Lake and Martin (Sawtooths), and Austera and Chalangin are each tied to the nearest foot based on Lidar. Currently for these tied peaks the peak with the highest Lidar-based elevation is listed higher, but this could change with a dGPS survey. None of these are close enough to the bottom of the list to affect which peaks are on the list, though. A future project could be to measure each of the remaining 87 peaks with dGPS for a dGPS WA Top 100 list.

It is likely that in future years St Helens will continue to erode. However, because it is already at number 101, its erosion will not affect the fact that it is not on the top 100 list. I would like to re-measure St Helens every year to track this erosion.

Rainier, Eldorado, and East Fury are all now rock summits, so while the icecaps near the summits will likely continue to melt, this will not affect the summit elevation of the peaks.

Colfax and Liberty Cap are still icecap peaks, and will likely change elevation in future years. I would like to re-measure these peaks every year to track this melting. However, neither of these peaks is close enough to the cutoff for elevation or prominence to be in jeopardy of leaving the list. Thus, the set of 100 peaks on the Lidar/dGPS WA Top 100 list is now stable.

Acknowledgements

I’d like to thank Steph S for loaning me her 1x sight level to survey Sherpa Peak in 2017 for my first WA Top 100 survey. Katie Stanchak advised on methodology and equipment for the duration of the project. Nick R, Steven S, Talon J, Ross Wallette, Josh Spitzberg, Salius Braciulis, Branden J, Daphne D, and Kahler K helped haul survey equipment up peaks and assisted with field measurements. Greg S gave valuable information about peaks through peakbagger.com and other correspondance, helped me understand the photo analysis tool developed by Edward Earl, and advised me on sight levels. Andy M helped estimate East Fury’s height based on other photo analysis.  Jake O gave valuable advice on the accuracy of Lidar. Compass Data engineers first taught me how to use a differential GPS unit. Dan helped double check my results post processing data from the differential GPS unit, which was loaned to me by Seattle University. Many members of the nwhikers forum gave valuable feedback about my methods and which peaks I should survey. Lily helped me take calibration measurements with the theodolite when I was learning to use it. Many professional surveyors from LSAW gave advice and helped process measurements.

© 2024, egilbert@alum.mit.edu. All rights reserved.