Surveying the Last Five Icecap Peaks of the Lower 48 States

Surveying the Last Five Icecap Peaks of the Lower 48 States

Eric Gilbertson

Assisted by Ross Wallette, Josh Spitzberg, Alden Ryno, and Salius Braciulis

Aug 27 – Oct 6, 2024

Summary

There have historically been five icecap peaks in the lower 48 states, all in Washington. As of this year three have melted down enough to now have rock summits, so only two icecap peaks remain. Mt Rainier melted 21.8ft, Eldorado Peak melted 20ft, and East Fury melted 30ft. All three now have rock summits. Liberty Cap melted 26.3ft but is still an icecap peak. Colfax is maintaining a steady elevation and is still an icecap peak.

Introduction

Until this year it was thought that there existed five icecap peaks in the lower 48 states. An icecap peak is a peak that has permanent ice/snow on the summit that persists throughout the year and never melts down to rock in the summer. The five icecap peaks, all in Washington State, are Mt Rainier, Liberty Cap, Colfax Peak, Eldorado Peak, and Mount Fury East Peak (aka East Fury).

This summer I started work on a project to measure the most up-to-date elevations of these peaks using professional surveying equipment (a differential GPS unit). I was concerned these peaks may be melting down due to climate change or other factors. Of the five only Mt Rainier had ever been measured with a differential GPS, but its summit was last measured in 1998. The other peaks had been measured with theodolites for the USGS quads, but these measurements were taken over 50 years ago. Some peaks had been measured by Lidar surveys in the past 10 years, but those values could still be outdated. I planned to take elevation measurements accurate to the nearest inch.

Methodology

For each peak I brought a differential GPS unit (Promark 220 with Ashtech antenna) to the summit and took a one hour measurement. In the case where the icecap summit melted lower than the nearby rock summit I measured the height of the new rock summit using the dGPS then used an Abney level (10 arcminute 5x Sokkia) to measure the relative height between the rock summit and icecap summit. In the case of Mt Rainier I took measurements on two different days on separate trips, and additionally measured all USGS monument on the mountain to corroborate results.

The standard time of year to measure icecap summits is at the lowest snow time of year for the mountain. This is so seasonal snow does not count towards the elevation and so results can be fairly compared from year to year. In Washington the lowest snow time of year is generally late August through September. I measured Rainier Aug 28 and Sept 21, Colfax Sept 3, Liberty Cap Sept 21, Eldorado Sept 28, and East Fury Oct 5.

I processed data using OPUS [6] and CRS-PPP [7].  These are publicly-available tools for processing data from differential GPS units and are provided by the US and Canadian governments. Additionally, professional surveyors processed the Rainier measurements using WSRN (the Washington State Reference Network) [8].

I was awarded a research grant by the American Alpine club for this study, and I used surveying equipment borrowed from Seattle University.

Mt Rainier

The most recent ground survey of Columbia Crest, the historical summit of Mt Rainier, was conducted on Aug 27, 1998 by the Land Surveyors Association of Washington (LSAW) [1]. To fairly compare the current elevation to that measured elevation I planned to survey as close as possible to Aug 27, 2024. I had to delay one day due to high winds, but was able to take a measurement on August 28. Josh Spitzberg and I climbed as an overnight trip, sleeping at Camp Muir on Aug 27 and ascending via the Disappointment Cleaver route on Aug 28.

I first mounted the dGPS on a mini prism tripod with 1.0ft antenna rod on the summit of the Columbia Crest icecap. I verified the location of the highest point with the abney level, and the highest point was ice. After the one hour measurement I moved the equipment to the southwest edge of the crater rim. I located the highest rock on the rim (which was the highest point on the entire summit area) using the Abney level, then mounted the tripod exactly on the top and took a one hour measurement.

I additionally took angular measurements with the Abney level looking down from the SW Rim to Columbia Crest, and looking up from Columbia Crest to the SW Rim.

I collaborated with professional surveyors to process the results, and presented my work at the September chapter meeting of LSAW surveyors in Bellingham, Washington. This group included members of the 2010 LSAW Rainier survey team. (That team measured the monuments on the mountain but did not measure Columbia Crest).

After consulting with LSAW surveyors I returned to Rainier on Sept 21 to take additional measurements to corroborate the previous findings. This time I was joined by Ross Wallette and Alden Ryno. I measured the SW Rim highpoint again, and also measured the elevations of the four monuments on the mountain – Paradise, McClure, Muir, and Summit 2. The Summit 2 monument had been stolen, so I measured the ground at the former monument location. Professional LSAW surveyors, including Larry Signani, processed the results.

I also compiled results from Lidar surveys from 2007 and 2022 [2], and historical survey results from 1956, 1988, 1998, and 2010 [3] of Columbia Crest and the SW Rim.

Liberty Cap

After measuring the summit of Rainier on September 21 I continued west to the summit of Liberty Cap. I used the Abney level to identify the highest point of ice, and took a one hour dGPS measurement with the 1.0ft antenna rod. I used the Abney level to measure an angular declination from the summit down to the Liberty Cap – Rainier col. I later processed Lidar data from 2007 and 2022 of the summit and col.

Colfax Peak

On September 3 I climbed Colfax Peak with Ross Wallette and Josh Spitzberg. I took a one hour measurement on the icecap summit with the dGPS. I also took a one hour measurement at the Colfax-Baker saddle, which I identified using the Abney level. I later processed Lidar data from 2015 and 2022 of the summit and col.

Eldorado Peak

One September 28 Ross Wallette and I climbed Eldorado Peak. The icecap had melted obviously lower than the rock outcrop to the west. I mounted the tripod on the rock outcrop and took a one hour measurement. I then used the Abney level to measure angular differences from the rock outcrop down to the icecap and from the icecap back up to the rock outcrop. I later found a photograph from late september 1950 [4] looking from the rock summit to the icecap. I used the Geopix photographic analysis software [5] to measure a relative height between the two locations from that photograph. I also found data from a Lidar pass in 2022 that measured both summits.

East Fury

Between Oct 5-6 I climbed East Fury with Ross Wallette and Saulius Braciulis. We hiked to Luna Camp the first day then to climbed to the East Fury summit on Oct 6. The icecap summit was obviously shorter than the rock summit, so I mounted the dGPS on the rock summit and took a one hour measurement. I was later provided a photograph by John Roper from 1980 looking from the rock summit to the icecap summit. I used the Geopix software to measure relative heights from this photograph. I later processed Lidar data from 2022 that measured both summits.

Results

[Note: all results are reported in NGVD29 vertical datum so current measurements can be fairly compared to past measurements, which were reported in that datum].

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 it was last measured. 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.

Discussion

Four out of the five icecap peaks of the lower 48 states have melted down between 20ft – 30ft in the past 20-70 years. Only one peak, Colfax, is maintaining elevation. Rainier started melting down in the early 2000s and in approximately 2014 the SW Rim overtook Columbia Crest as the summit. Liberty Cap started melting down at a similar time. There is not enough data to determine exactly when East Fury and Eldorado started melting down. However, it is likely for East Fury the rock summit overtook the icecap summit sometime in the early 2000s. For Eldorado Peak the rock summit likely overtook the icecap summit between 2019-2021.

Conclusion

Of the former five icecap peaks in the lower 48 states, all in WA, only two now remain icecap peaks – Liberty Cap and Colfax Peak. Rainier, Eldorado, and East Fury icecap summits have all melted down 20-30ft and these peaks now have rock summits.

Acknowledgements

Funding was provided by the American Alpine Club, with equipment provided by Seattle University. Surveyors from the 1988, 1998, and 2010 LSAW teams helped plan methodology and processed results for Mt Rainier. Katie Stanchak advised on methodology and equipment and data analysis. Dustin W. and John Roper provided summit pictures for photographic analysis. Kyle B. helped with Lidar processing. Rainier climbing rangers and guides kept the DC route open so we could make it up to the summit for the first measurement. IMG guide Justin Sackett provided valuable beta so we could reach the Rainier summit for the second measurement after ladders had been pulled on the DC route.

References

1. Signani, L., “The Height of Accuracy,” July 19, 2000, Point of Beginning, https://archive.ph/IVhw#selection-1113.5-1113.26 

2. Washington Lidar Portal https://lidarportal.dnr.wa.gov/

3. Schrock, G. “Rainier – The Unforgiving Mountain,” Jan 27, 2011, The American Surveyor, https://amerisurv.com/2011/01/27/rainier-the-unforgiving-mountain/  

4. Misch, P. “Climber on summit of Eldorado Peak, Washington, September 19, 1950,” University of Washington Libraries, https://digitalcollections.lib.washington.edu/digital/collection/epic/id/13272/ 

5. Earl, E., 2017, “GeoPix Photo Analysis,” available for download at https://github.com/ericgilbertson1/PhotoAnalysis/tree/main

6. Online Positioning User Service (OPUS), NOAA, https://geodesy.noaa.gov/OPUS/

7. Precise Point Positiong processing, https://webapp.csrs-scrs.nrcan-rncan.gc.ca/geod/tools-outils/ppp.php?locale=en&_gl=1*1as3oua*_ga*NTQ2NTE3OTMwLjE3MTQ2NzgzMjU.*_ga_C2N57Y7DX5*MTcyNjA4NjU

8. Washington State Reference Network, http://www.wsrn.org/

 

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