Glaciers in CO

[Hiking_TheRockies]

Took this photo during a climb of Navajo Peak in the IPW. I'm not sure if this large mass of snow on the north side of Arikaree Peak is a glacier or just a permanent snowfield. It's in the Boulder County Watershed, so I don't know how many people have been over there. Any history behind this one?

[Scott P]

Took this photo during a climb of Navajo Peak in the IPW. I'm not sure if this large mass of snow on the north side of Arikaree Peak is a glacier or just a permanent snowfield.

It's a small glacier. You can see some crevasses above the lake and a bergschrund near the rock wall.

[justiner]

Ugh, just seeing that peak makes me want to do that ridgeline above the glacier

[HikerGuy]

Took this photo during a climb of Navajo Peak in the IPW. I'm not sure if this large mass of snow on the north side of Arikaree Peak is a glacier or just a permanent snowfield. It's in the Boulder County Watershed, so I don't know how many people have been over there. Any history behind this one?

Here's a deep dive on the recent history of the Arikaree Glacier:
https://www.colorado.edu/honorsjournal/ ... alance.pdf

[jibler]

Castle Peak has a cool one

nestled up in that high north side cirque thing


big question - where is the furthest south 'glacier' in Colorado?

[Scott P]

big question - where is the furthest south 'glacier' in Colorado?

Some sources say Blanca, but it may have melted.

Although it's not on any maps, as you point out Castle has a small galacierette. Since it does have small crevasses, it should qualify.

[Harlan U]

big question - where is the furthest south 'glacier' in Colorado?

There was a pair of small glaciers under the north face of Blanca Peak in the early 1900s. Modern photos show two snowfields in the same spot. I don't think they are glaciers anymore.
https://glaciers.us/glaciers.research.p ... rra_Blanca

There may have been a number of glaciers in the Wilson Group as late as the 30s, as a few photos from the CU Boulder collections indicate. https://cudl.colorado.edu/luna/servlet/ ... =12&trs=20

Currently, the farthest south glacier is Arapaho, and it is very certainly still a real by-definition glacier. It meets the commonly used size requirement of 25 acres, and has a number of crevasses demonstrating movement.

[martinleroux]

I'm not sure if this large mass of snow on the north side of Arikaree Peak is a glacier or just a permanent snowfield. It's in the Boulder County Watershed, so I don't know how many people have been over there.

Although it's is on the NE side of the divide, a big chunk of it outside the Boulder Watershed. (That's also true of the upper part of the Arapaho Glacier). Rumor has it that quite a few people doing the LA Freeway traverse have filled up at that tarn.

Screenshot 2022-11-28 220206.jpg (160.44 KiB) Viewed 749 times

[Scott P]

big question - where is the furthest south 'glacier' in Colorado?

There was a pair of small glaciers under the north face of Blanca Peak in the early 1900s. Modern photos show two snowfields in the same spot. I don't think they are glaciers anymore.
https://glaciers.us/glaciers.research.p ... rra_Blanca

There may have been a number of glaciers in the Wilson Group as late as the 30s, as a few photos from the CU Boulder collections indicate. https://cudl.colorado.edu/luna/servlet/ ... =12&trs=20

Currently, the farthest south glacier is Arapaho, and it is very certainly still a real by-definition glacier. It meets the commonly used size requirement of 25 acres, and has a number of crevasses demonstrating movement.

That's a really good site that you're referencing (I have used it often), but it's one flaw is that it only studies and shows glaciers or snowfields that show up on the USGS maps. For some reason, the surveyors didn't bother showing the perpetual snow or ice bodies in the Elk Mountains, even though they do exist. At least two bodies of ice in the Elks do show movement and crevasses. They are the one below Castle Peak and the one below Hagerman and Snowmass Peaks. These ones do show crevasses after the seasonal snow melts off, at least for now.

Here's a screenshot of the crevasses in the small "glacierette" on Hagerman/Snowmass Peak.

Hagerman.png (436.78 KiB) Viewed 744 times

Due to the presence of crevasses, these two ice bodies are probably small glaciers (I can't say 100% sure), but I have never seen studies on them. It's a good bet that both are active glaciers, albeit small.

[XterraRob]

What area of Colorado had the last remaining significant glacial coverage? I would have thought the San Juans given the average elevation, and amount of rock glaciers around Gilpin, Dallas/West Dallas, and surrounding areas. I seem to remember reading somewhere it was the Front Range around Boulder though.

[Harlan U]

That's a really good site that you're referencing (I have used it often), but it's one flaw is that it only studies and shows glaciers or snowfields that show up on the USGS maps. For some reason, the surveyors didn't bother showing the perpetual snow or ice bodies in the Elk Mountains, even though they do exist.

You make a good point! I'm absolutely certain a number of real glaciers are totally undocumented. USGS maps are pretty dated and make no distinction between glaciers and permanent snow, so they're not usually the best tools to try and find unnamed glaciers. I prefer to use satellite imagery to locate them, but it's often taken while snow is still present, leaving any glacial features completely hidden within the snow. A lot of glaciers go completely unnamed and unknown because of this.

[Harlan U]

What area of Colorado had the last remaining significant glacial coverage? I would have thought the San Juans given the average elevation, and amount of rock glaciers around Gilpin, Dallas/West Dallas, and surrounding areas. I seem to remember reading somewhere it was the Front Range around Boulder though.

The Indian Peaks and RMNP contain almost all of the current glaciers. I think their placement has something to do with the amount of blowing snow that creates isolated areas of extremely deep snowpack in certain cirques. Essentially the same effect that creates cornices, but on a big scale. Scientific studies i've read seem to indicate that they receive most of their snow through avalanching.