Rainier and Liberty Cap Surveys 2025

Rainier and Liberty Cap Surveys Aug 2025

Aug 24-25, 2025

Summit team: Eric, Branden, Josh, Peter, Scott, Anthony
Lower mountain team: Ethan, Darin, Shannon
Geodecist: Larry Signani, Trimble Engineers

Results (NAVD88 vertical datum)

SW Rim: 14,406.3 ft +/- 0.1 ft
Columbia Crest 14,394.6 ft +/-0.1 ft
Liberty Cap: 14,094.9 ft +/- 0.1 ft

Columbia Crest melted down 1.2 ft since Aug 28, 2024
Liberty Cap melted down 2.2 ft since Sept 21, 2024

Columbia Crest ice is 16.5ft thick on the summit. Melt rate is 0.9ft/year and it will likely melt to rock by 2045.
Liberty Cap ice is 34.8ft thick on the summit. Melt rate is 1.6ft/year and it will likely melt to rock by 2047. It will likely melt below nearby rock summit and lose icecap peak status by 2041.

Link to preprint scientific paper about the results: RainierElevationSurvey2025

Note: Rainier National Park reports the elevation in NGVD29, an older vertical datum, though NAVD88 is the current standard. In this report I’m using NAVD88 to be consistent with the modern standard datum.

Introduction

In 2024 in August and September I took elevation measurements of Rainier and Liberty Cap using a survey grade dGNSS unit capable of 0.1ft vertical accuracy. Historically, the summit of Mt Rainier has been Columbia Crest, a permanent ice peak on the west edge of the crater rim. This was measured in 1956, 1988, and 1998 and maintained roughly constant elevation over this period. All measurements were conducted in late summer,  generally in August.

Columbia Crest was not measured by ground surveys between 1998-2024. When I measured it in late August, 2024, I discovered it had melted down 21.8 ft since 1998. It was, in fact, no longer the highest point of Mount Rainier. The new highest point was on the rocky SW crater rim about 440ft away. This point was 10.4ft taller than Columbia Crest, a difference that is noticeable to the naked eye even at that distance. 

I’m interested in continuing to study this melting, which has only started occuring since 1998. The major questions I’ve been interested in for 2025 are: 

1. How much elevation did Columbia Crest lose between late Aug 2024 to late Aug 2025?
2. How many days did Columbia Crest get above freezing in summer 2025?
3. How much snow accumulates on Columbia Crest over the winter?
4. How thick is the Columbia Crest ice?
5. In how many years will Columbia Crest be gone?  

I got an official research permit from the park to collect data to answer these questions. 

In early May this year, at the approximate max snow depth time of year based on the paradise SNOTEL sites, I took an elevation measurement of Columbia Crest using a Trimble DA2 dGNSS unit (link to report). I found only 0.5ft of snow had accumulated since Aug 28, 2024. This indicated that snow generally blows off Columbia Crest in the winter and does not accumulate. I measured that Liberty Cap had 6.6ft of snow accumulation since Sept 2024. So it accumulates a bit more on Liberty Cap. 

There are no weather stations on the summit, so it’s hard to know exactly how warm it gets. But the weather forecast most trusted by the national Park and climbing rangers is the UW Rainier recreational forecast, which forecasts freezing levels for the mountain and summit temperatures. 

Beginning in early June, I wrote a script to save this forecast daily. I found that by Aug 24, the summit had gotten above freezing 28 days (meaning forecast freezing level for the current day forecast was 14500ft or higher). That would likely translate into significant melting. Since I’d discovered snow doesn’t really accumulate on the summit, Columbia Crest would likely shrink down further. 

In late August I planned to return to take elevation and ice thickness measurements. I wanted to take measurements at as close as possible a date to previous measurements so they could be fairly compared. In general icecap peaks are measured at the lowest snow time of year in late summer. In Washington this is approximately late Aug to early Sept on Mt Rainier. The last measurement when Columbia Crest was maintaining elevation was Aug 27, 1998. My 2024 measurement was Aug 28, 2024. 

I wanted to choose the closest weekend to these dates, which was the Aug 23-24 weekend. If I could take measurements on that weekend, they could be fairly compared to previous measurements. 

After consulting with surveyors from the land surveyors association of Washington (LSAW) I decided the most rigorous survey plan was to take simultaneous static measurements at each of the three monuments on the lower mountain (Paradise, McClure, and Muir), at the same time as measurements on the SW rim and Columbia Crest. Measurements would need to be at least two hours, but ideally longer. I would need five different dGNSS units, and people to operate them at each location. 

There used to be a monument on the SW rim near the highpoint, but every time surveyors have gone up it has been stolen. It was last replaced in 2010, but had been stolen again by the time I surveyed in 2024. Rainier national park did not give me permission to replace it, so the plan was to measure the highest point of the mountain on the SW rim, then bluebook that location. That would effectively make that location the new one to measure for future surveys instead of the monument (which wasn’t there anyways). 

To measure ice thickness, I borrowed a Noggin 100 ground penetrating radar unit from Earthscope. They mailed the device to Branden’s house, then he took the lead on figuring out how to use it. He made a custom frame that attached it to an expedition pulk, and the total setup was around 65lbs. 

Trimble very generously offered to lend me four DA2 units, which are top-of-the-line new dGNSS receivers and are ultralight. This was important for the upper mountain. 

In addition to measuring Rainier, I also wanted to measure how much Liberty Cap had melted down in the last year. Liberty Cap is one of the five historic icecap peaks in the contiguous US (Rainier, Liberty Cap, Colfax, Eldorado, and East Fury). These summits have historically had permanent icecap summits that did not melt down to rock in summer. In 2024 I discovered that of these five, only Liberty Cap and Colfax still have permanent icecap summits. The others lost icecap peak status in approximately 1990 (East Fury), 2014 (Rainier) and 2020 (Eldorado). 

I wanted to predicted how much longer Liberty Cap would remain an icecap peak, so I would measure its current elevation to see how much it melted in the past year, and measure the thickness of the ice on the summit, to predict how much longer it would last at current melt rates. 

The total weight of survey gear to haul up was about 80 lbs. I planned to recruit a team of six climbers for the summit team to distribute the weight. We would climb as a single push car-to-car trip to avoid carrying extra weight of overnight gear.

Branden, Peter, Scott, Anthony, and Josh agreed to join. For the lower monuments, Ethan volunteered to occupy the Muir Monument, Darin would take McClure, and Shannon would take Paradise. 

The McClure monument was on top of a boulder and relatively easy to find, but the Paradise and Muir monuments were buried (to prevent vandalism and theft). Ethan was experienced at finding buried monuments, and wrote special custom software to interface with the DA2 measurements to help locate the exact location with known coordinates provided by LSAW. These monuments were last measured in the 2010 Rainier survey, and were buried between 0.5-1ft underground.

With the team sorted out, I planned to pick whichever day of the weekend had the best weather, and go for that day. We would meet at Paradise the afternoon before, pick up a climbing permit, then locate the Paradise monument. The summit team would start up at midnight, and plan to reach the summit at 10am. Darin and Ethan would hike up and locate their monuments that morning, and they and Shannon would all start logging data by 10am. We had radios and inreach satellite texting devices to coordinate in case of any schedule changes. 

I would first set up the DA2s on 2m antenna rod tripods on the SW rim and Columbia Crest. Then Branden would assemble the GPR and take Columbia Crest ice thickness measurements. Then two people would stay with the dGNSS units to guard them while the remaining four moved over to Liberty Cap. 

On Liberty Cap Branden would take GPR measurements and I’d take a one hour elevation measurement. We’d then return, log the GNSS data on Rainier (likely at least 4 hrs of data), then head down back to Paradise.

In the mountains I’ve learned no survey ever goes completely as planned. Conditions are always challenging and time is always tight. I would bring one extra DA2 unit and extra batteries just in case, and an Abney level and digital clinometer to measure angles between SW rim and Columbia Crest. This would help corroborate the dGNSS data for relative heights. 

The week before Rainier I got practice carrying the GPR rig solo in to East Fury (50 miles round trip in two days with 70lb pack), and Branden got practice collecting data on Colfax. On Wednesday I made the call that Sunday would be our summit day. 

Saturday afternoon I drove to Paradise by 2pm and picked up a climbing permit for our group. Each member had paid the annual climbing fee in advance and given me the confirmation number, and I was able to fill out all the information on my own (the other team members did not need to be present). 

I then went over and found Ethan and Shannon working on locating the Paradise monument, which is in the dirt on the shoulder on the SE side of the upper day parking lot. A ranger/law enforcement person came over to us and was angry at us for digging around and told us what we were doing was illegal. I told him we actually had permission from the park to do this, and we handed him a printed out permit specifically giving us permission to do that. He took it, went in some building, then came back 10 minutes later and said we could continue. 

Ethan soon located the monument, which was exciting to see. It was like finding buried treasure! By then the rest of the team had arrived and I got everyone organized down in the overnight lot and distributed gear. We had dinner at the Paradise Inn, then returned to the lower lot for a few hours nap in our cars.

By midnight we were up and moving. We made good time up to Pebble Creek, then soon after reached continuous snow. We ditched our approach shoes there and switched to mountaineering boots and crampons. The Muir snowfield had several long ice patches. I think it melts out a lot more than it used to. When I first climbed Rainier in 2007 in late August I descended the Muir snowfield and it was all snow, but now it regularly melts down to ice late season.

By 530am we reached camp Muir, and roped up for the glacier. Anthony decided to return there, and I took his group gear in my pack. 

 We crossed the Cowlitz glacier as the sun rose, then short-roped up over Cathedral Gap to Ingraham Flats. We then crossed to the Disappointment Cleaver, and short-roped scrambling up the cleaver. 

By then many guided groups were descending, and I think they’d topped out at sunrise. Some of them said they turned around early since it was too late in the day to comtinue. The route was in great condition, though, so I saw no problem with being on it in the middle of the day or later in the day. I expected we would probably be up there most of the day and descend in the evening.

By the time we topped out on top of the cleaver I knew we were well behind schedule. I had line of sight to Muir and at 930am radioed Ethan that our new ETA would be noon at the summit. It was important to try to not get too far behind schedule so we could get all the planned measurements. 

To speed things up a bit I took some more group gear, then Scott and I decided to move up as fast as possible on a rope team to get the GNSS devices set up. 

Shortly after we got back on the glacier the route traversed far right to gain the Emmons Shoulder. This is pretty typical later in the season for the DC route. A big crevasse generally opens up around 12800ft, and must be crossed either with ladders, or gone around. If you can make it to the Emmons Shoulder the crevasses are generally not problematic above that. The guides from RMI and Alpine Ascents always do an amazing job figuring out a perfect route so recreational climbers like us can make it up. We just follow the route they establish.

We reached the shoulder, after crossing a few horizontal ladders. We then moved up as a few more teams descended. We reached the SE rim by a bit after noon, and I knew from there to the summit was crevasse-free. So I had Scott keep the rope while I hustled over to the SW rim with the survey gear. 

I quickly mounted the tripod and DA2 on the boulder that marked the highest point of the mountain by 1230pm. I then hustled over to Columbia Crest, and got the next receiver mounted on a tripod by 1245pm. There was no radio connection there, but I inreach messaged Ethan that I’d started, and he said everyone on the lower monuments had already started logging data and would go for at least three more hours.

Interestingly, Columbia Crest now had a shallow crevasse going almost directly over the summit! That wasn’t there last August or September, and it looked like Columbia Crest is falling apart. 

I took Abney level and clinometer angular measurements from SW rim down to Columbia Crest and from Columbia Crest up to SW rim. These were consistent, showing a 1.5 degree +/-5 arcminute declination, which at that distance translates to Columbia Crest being 11.4ft +/-0.8ft shorter than SW rim. Last year it was 10.4 ft shorter, so those preliminary measurements showed it had melted down around a foot in the last year. That was consistent with Columbia Crest falling apart with that crevasse. I would have to wait for the GNSS measurements to be processed to be certain about the numbers though.

By 2pm the rest of the crew arrived and we helped Branden set up the GPR unit in the pulk and got it running properly. He pulled it all around the Columbia Crest summit, and collected a lot of good data. 

By 3:30pm we partially packed it up and started over for Liberty Cap. Peter and Scott stayed to guard the equipment. We left the antennas and main Noggin unit attached to the pulk and I strapped that whole setup to my pack. Then Branden carried the frame. Leaving it together would save us valuable time on Liberty Cap. Josh joined and carried other survey gear and we were a three-man rope team.

I led the way over, since I was pretty familiar with the best route from my recent trips in September and May. We descended to the Liberty Cap- Rainier col, then followed the NE ridge. Interestingly, we started encountering penitentes that got more and more extreme the closer we got to the summit. There hadn’t been any penitentes on Columbia Crest. 

I started weaving through crevasses and soon reached a dead end. We had to turn around and find a new route, so Josh took the lead. He found a good snow bridge, then led the way up the east ridge, scrambling over and around increasingly crazy penitentes. Some were 5ft tall, and I’ve never seen them that extreme in Washington. Only at high altitude in the Andes have I seen them like that. Last September on Liberty Cap there were some, but much smaller. Interestingly, unlike in South America, these penitentes were all at angles, not vertical. They were generally leaning towards the SE. 

By 515pm we reached the summit. It was challenging, though, to pick out the exact highest point. It probably shouldn’t be the tip of a penitente, since that will likely soon fall over. But it probably shouldn’t be the bottom of the cracks between the penitentes.

I ended up going to the location that was highest last September and in May, and mounted the DA2 on the flattish snow between penitentes. 

 

Branden found a semi flat stretch of snow next to this, and assembled the GPR. He then dragged it around and took ice depth measurements. 

By 630pm we logged all our data and packed up. We made faster time back, and got to Columbia Crest by 730pm. This was a bit later than planned, but I was very happy that we got all the data and still had some daylight left. 

 

I quickly packed up the GNSS gear, and unfortunately noticed that the SW rim phone had lost Bluetooth connection at 330pm and stopped logging data. I still got three hours of data, which was plenty, but it would have been amazing to get the full 7 hours.

The Columbia Crest unit appeared to have been on the full 7 hours, which was great. I packed up and met the rest of the team on the SE rim ready to head down. But just to be absolutely certain I had the data, I decided to look for the data file from the Columbia Crest setup. 

For this one I’d used a Trimble phone instead of my own, and I wasn’t quite as familiar with it. I tried looking everywhere on the phone, but couldn’t locate the data file. I was very worried that it hadn’t saved any data! 

I suspected the file was buried somewhere on the device, but just to be safe I wanted to go and log a bit more data on my own phone as a backup. Peter volunteered to stay with me and the rest of the crew started down. 

I rushed back over to Columbia Crest, set up the unit, and started logging data again at 9pm. The lighting was great with the sun setting and the clouds clearing out. I think plenty of people see sunrise in Rainier, but it’s a rare treat to see sunset. 

I hung out admiring the view for 30 minutes, which generally gets me around 0.15ft vertical accuracy. I figured that was sufficient backup data to at least have something, so then packed up.

We started down by 10pm, and made steady progress down to the Disappointment Cleaver. We then unroped and scrambled down, and roped back up at the base. By then it was 1:30am and groups were already starting up. We passed an enormous group of dozens of guided clients, but after that we were on our own. 

We took a short break at Camp Muir around 2:30am, then made it back down to Paradise by 6am, just as hikers were starting up. It had been a 30hr push, a bit longer than anticipated, but we got all the data as planned.

Ethan and Shannon met us in the parking lot and gave us a great breakfast. I probably should have taken a nap, since I had pretty much been up for 48 hrs straight (I hadn’t really slept Saturday night). But by then the lot was getting busy with hikers arriving. I decided it would be too loud to sleep, so I just started driving out with Branden. 

By 9am I found a quiet pullout to take a one-hour nap, then made it home by noon. I later managed to find the hidden data from the Columbia Crest receiver, and it had indeed recorded the full 7 hours of data. So all measurements were indeed collected as planned. 

Results:

Data were processed with Trimble Business Center (TBC 2025), Online Positioning User Service (OPUS 2025), OPUS Projects (OPUS Projects 2025), Canadian Spatial Reference System Precise Point Positioning processing (CSRS-PPP 2025), Trimble RTX (Trimble 2025), and AUSPOS Online GPS Processing Service (Jia 2014). We report the OPUS results but note that the TBC, OPUS Projects, CSRS-PPP, Trimble RTX, and AUSPOS methods gave similar, consistent values. Results will be reported in meters and US Survey feet in NAD83 (2011) Epoch 2010, NAVD88 (Geoid 18). This is the current standard datum output by OPUS.

Location	Elevation m (ft)	Sigma m (ft)	Lat	Lon
SW Rim	4391.04 (14406.3)	0.02 (0.07)	46° 51’ 06.21562”	-121° 45’ 37.43064”
Columbia Crest	4387.47 (14394.6)	0.02 (0.07)	45° 51’ 10.553091”	-121° 45’ 38.20381”
Liberty Cap	4296.13 (14094.9)	0.02 (0.07)	46° 51’ 46.50016”	-121° 46’ 28.75120”
Muir	3076.29 (10092.8)	0.09 (0.28)	46° 50’ 07.81199”	-121° 43’ 56.44798”
McClure	2252.15 (7389.8)	0.02 (0.07)	46° 48’ 31.07171”	-121° 43’ 22.36721”
Paradise	1644.09 (5394.0)	0.01 (0.02)	46° 47’ 06.91811”	-121° 44’ 03.82096”

The summit of Mt Rainier on the SW Rim was measured to be 4391.04 m +/-0.04m (14406.3 ft +/-0.1 ft) (95% confidence interval). This is consistent with the reported 2024 measurements of 4391.01 m +/-0.03 m (14406.2 ft +/-0.1 ft) (95% confidence interval errors).

Columbia Crest was measured to be 4387.47 m +/-0.04 m (14394.6 ft +/-0.1 ft) (95% confidence interval errors). This means Columbia Crest lost 0.37m (1.2ft) of elevation between Aug. 28, 2024 and Aug 24, 2025.

Thus, as of Aug. 2025, the SW Rim is 3.57 m (11.7 ft) taller than Columbia Crest and is the highest point on Mount Rainier.

All GNSS measurement processing methods were consistent that the SW Rim is higher than Columbia Crest. This can be seen in box-and-whisker plots. Measured elevations are over 50-sigma apart, meaning it is essentially statistically certain that the SW Rim is higher than Columbia Crest.

Abney level measurements found an angular inclination of 1.5 degrees 5 arcminutes up from Columbia Crest to the SW Rim and 1.5 degrees 5 arcminutes down from the SW Rim to Columbia Crest. The horizontal distance is 133 m (436 ft) between them, which means the measured height difference from basic trigonometry is 3.47 m +/- 0.02 m (11.4 ft +/-0.8 ft). This is consistent with the 11.7 ft height difference measured by the GNSS units.

Liberty Cap was measured to be 4296.13 m +/- 0.04 m (14094.9 ft +/- 0.1ft). Liberty Cap melted down 0.67 m (2.2ft) from Sept. 21, 2024 to Aug. 24, 2025. It still had ice at its highest point, so it is still an ice-capped peak.

GPR Results

Five data lines were measured on Columbia Crest by the Noggin GPR device, and one representative line is shown. This line was 130 m long and started northeast of the summit, then followed a clockwise spiral ending on the summit.

The surveyed area of Columbia Crest has an ice thickness between 1 m–5 m (3.3 ft – 16.5 ft). The ice is 5 m (16.5 ft) thick on the exact summit. Subtracting the ice thickness from the measured elevation of the Columbia Crest summit means the underlying bedrock has a measured elevation of 4382.44 m (14378.1 ft).

We fit a linear model to the portion of elevation measurements between 1998 – 2025, when Columbia Crest has been melting down. This fit was highly linear, with an R² of 0.990 and slope -0.9 ft/year. Columbia Crest has been losing -0.9 ft per year of elevation since 1998. At this rate, assuming the same melt rate persists in future years, the Columbia Crest icecap will fully melt by approximately 2045.

For Liberty Cap two GPR data lines were collected, and the longest is shown. This line was 11 m (36.1 ft) long, started on the summit, and moved in a clockwise direction. The surveyed area of Liberty Cap has an ice thickness between 10.6 m – 13.0 m (34.8 ft – 42.7 ft). The ice is 10.6 m (34.8 ft) thick on the exact summit. Subtracting the ice thickness from the measured elevation of Liberty Cap means the underlying bedrock has a measured elevation of 4285.52 m (14060.1 ft)

The elevation of the highest visible rock outcrop on Liberty Cap has been found based on LiDAR measurements (Gilbertson 2025) to be at an elevation of 14069.4 ft. If Liberty Cap melts below this elevation it will no longer be an icecap peak.

Elevation measurements for Liberty Cap are plotted for data between 1956 and 2025. A linear model is fit to the data between 2007 and 2025 when Liberty Cap has been melting down. This model is also highly linear, with an R squared value 0.998 and a slope of -0.49 m (-1.6 ft) per year.

This means Liberty Cap has been melting down at an average rate of -0.49 m (-1.6 ft) per year since 2007. If this melt rate continues, the summit will melt below the elevation of the highest visible rock by 2041, and Liberty Cap will no longer be an icecap peak. By 2047 Liberty Cap will melt down to bedrock.

Temperatures

It is difficult to know the exact temperature on the summit, because there is no automated weather station on the summit. Climatologist Dr. John Abatzoglou has modeled the summit temperature between 1950 – 2024 (see figure) and the summit has gotten above freezing nearly every year. But, the degree days above freezing have increased significantly starting in the early 2000s. This is the same time when the summit started losing elevation, and the synchronous timing means the elevation loss is most likely due to melting. (See Gilbertson et al 2025 for a scientific journal paper about 2024 measurements and climate analysis).

Temperature analysis from 2025 is planned for a future paper. But, one way to approximate how warm the summit got in summer 2025 is to look at the weather forecast that is most-trusted by climbing rangers and park staff for the summit. That is the twice-daily University of Washington Rainier Recreational Forecast (https://a.atmos.washington.edu/data/rainier_report.html). This forecasts summit temperature and freezing level elevation.

Unfortunately this forecast information is not saved by the University of Washington (I asked). But I wrote a python script that saves the forecasts daily. I started running it in early June when I first noticed the summit getting above freezing in the forecasts. Between June 6 – Aug 24, when the summit elevation survey was conducted, there were 28 days with forecast freezing levels above the summit elevation (freezing levels 14,500ft or higher). So 28 out of 78 days were above freezing on the summit. This is a little over one out of every three days, a significant proportion. Between Aug 25 – Sept 25 an additional seven days were above freezing, with the last one on Sept 24. A total of 35 days were forecast above freezing on the summit over the summer.

Discussion

The true summit of Mt Rainier is the SW Rim, at 4391.04 m +/-0.04 m (14,406.3 ft +/-0.1 ft) (95% confidence interval). This has been the summit since approximately 2014. It was still measured as the highest point in 2025, consistent with 2024 results.

Columbia Crest began melting down in 1998 and has been melting at a surprisingly linear rate (R squared 0.990), losing 0.027 m (0.9 ft) each year very consistently. It is unclear why this rate is so linear and not accelerating. Future work could investigate in detail if the modeled temperatures on the summit have similarly increased linearly. Though, without direct temperature measurements on the summit it is hard to know for certain what past temperatures were. If temperature could be measured directly on the summit for one summer season, it may be possible to calibrate temperature models from past years to get a more accurate idea of past summit temperatures.

Columbia Crest was measured to be only 5 m (16.5 ft) thick at the summit in 2025. At current melt rates, it will melt to bedrock by 2045 (Fig 15).

Columbia Crest only accumulated 0.15 m (0.5 ft) of snow between late summer 2024 and spring 2025, at the approximate maximum snow depth time of year. Certainly much more snow than this falls on the summit. One possible explanation is that it all gets blown off and does not accumulate. The accumulation in May appeared to be more rime than snow, which may be because rime can form in high wind while snow might get blown off.

This leads to a potential explanation of the seasonal and long-term behavior of the elevation of Columbia Crest. Before 1998, Columbia Crest appeared to be at a steady-state elevation based on all measurements. In the winter and spring snow did not accumulate because it was mostly blown off. In the summer Columbia Crest did not melt down appreciably because it rarely got above freezing (see Gilbertson 2025).

However, beginning in the late 1990s or early 2000s, the temperature at the summit began getting above freezing a significant amount. In each of these years it still did not accumulate much snow in the winter/spring, but it began melting down approximately 0.27 m (0.9 ft) every summer. That trend has continued through 2025.

It is unknown exactly how Columbia Crest formed, and why or when snow might have accumulated in that area. If ice cores could be taken into Columbia Crest, different layers of historical accumulation could be examined and dated. That could potentially reveal information about when and how fast Columbia Crest formed.

Liberty Cap started melting down around 2007 (or perhaps earlier, though no measurements exist between 1956 – 2007). It has been melting at a highly linear rate (R squared value 0.998), just like Columbia Crest has. If the current melt rates continue, it will no longer be an icecap peak by 2041 (Fig 16). As of 2025 there are only two icecap peaks remaining in the contiguous US – Colfax peak and Liberty Cap. Colfax peak will likely lose its status as an icecap peak within a few years at current melt rates (a paper about this is in preparation). This means Liberty Cap will likely be the last remaining icecap peak in the contiguous USA soon, and by 2041 there will no longer be any icecap peak in the contiguous USA. (Note: Columbia Crest now counts as a sub-peak of Mt Rainier because it has such low prominence).

Interestingly, the elevation loss rate of Liberty Cap is almost twice the rate of Columbia Crest. This phenomenon of different elevation loss rates has been documented on other pairs of nearby icecap peaks around the world, such as Pico Bolivar and Pico Colon in Colombia (Gilbertson et al, in review). It is possible that differences in icecap peak shape have a strong affect on their elevation loss rates because this affects wind scouring and winter accumulation.

Also, Columbia Crest is about 300ft taller than Liberty Cap, which would result in about 1 degree F colder temperature (assuming a standard lapse rate of 3.5°F per 1000 ft). It is possible freezing levels are often at Liberty Cap elevation but just below Columbia Crest elevation. More detailed temperature data would be needed to understand this.

Liberty Cap accumulated 6.6 ft of snow between Sept. 21, 2024 and May 6, 2025. This was over 10 times the accumulation on Columbia Crest, even though the peaks are only 1.6 km (1 mile) apart horizontally. This is possibly because wind affects are less pronounced on Liberty Cap, and less snow gets blown off the top. Columbia Crest is at a higher elevation and is thus likely subject to stronger winds.

Conclusion

Columbia Crest melted down 0.37 m (1.2 ft) between late summer 2024 and late summer 2025 and had an ice thickness of 5 m (16.5 ft) at the summit in 2025. Melt rates were highly linear, and if the current rates continue into the future, it will melt to bedrock by 2045. Only a minimal amount of snow (0.15 m/0.5 ft) accumulated on Columbia Crest in winter/spring 2025.

Liberty Cap melted down 0.67m (2.2ft) between late summer 2024 and late summer 2025. If current highly linear melt rates continue it will no longer be an icecap peak by 2041, and will melt to bedrock by 2047.

The Southwest Rim is still the highest point on Mt Rainier, with an elevation of 4391.04m +/- 0.04 m (14,406.3 ft +/- 0.1 ft) (NAVD88).

Data Availability

Raw measurement files are available at: https://drive.google.com/drive/u/0/folders/1sZM3rWVBY5cJwaRu41GiaI8cGl72rGw9

References

Arhuber, Rainier summit view June 27, 2009, https://www.youtube.com/watch?v=qDQ6jqAs2h0

Beason SR and Others. 2023. Changes in glacier extents and estimated changes in glacial volume at Mount Rainier National Park, Washington, USA from 1896 to 2021. Natural Resource Report. NPS/MORA/NRR—2023/2524. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2299328

CSRS-PPP. 2024. Canadian Spatial Reference System Precise Point Positioning processing.

Gilbertson, E., Abatzoglou, J., Stanchak, K., Hotaling, S., “Rapid shrinking and loss of ice-capped summits in the western USA,” Arctic, Antarctic, and Alpine Research Journal, 2025 Access at: https://www.tandfonline.com/doi/full/10.1080/15230430.2025.2572898

Gilbertson, E., Stanchak, K., Hotaling, S., “Contemporary Shrinking of Colombia’s Highest Mountains: Pico Simón Bolivar and Pico Cristóbal Colón,” Geografiska Annaler: Series A, Physical Geography, (in review)

Jia, Minghai, Dawson, John, Moore, Michael, “AUSPOS: Geoscience Australia’s On-line GPS Positioning Service,” Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014), Tampa, Florida, September 2014, pp. 315-320

Mount Rainier National Park, 2024 https://www.nps.gov/mora/index.htm 

NGS Coordinate Conversion and Transformation Tool (NCAT), 2025 https://www.ngs.noaa.gov/NCAT/

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