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Beneath crumbling walls: how rock glaciers took over the southern rockies

Gabe Allen — Wed, 18 Jun 2025 22:24:17 +0000

Beneath crumbling walls: how rock glaciers took over the southern rockies Gabe Allen Wed, 06/18/2025 - 16:24

Gabe Allen

20,000 years ago, during the last glacial maximum, hulking formations of flowing ice stretched across the Southern Rocky Mountains in present-day Colorado. Most of those glaciers melted away by around 13,000 years ago, but that doesn’t mean Colorado’s glaciers are gone. They’ve just gone underground. Today, the state is home to thousands of rock glaciers — icy formations protected by layers of debris.

“Anybody who climbs the fourteeners of Colorado, whether they know it or not, is climbing across a rock glacier here or there,” INSTAAR fellow and distinguished professor of geologic sciences Robert Anderson explained.

Last month, Robert Anderson and Suzanne Anderson, also an INSTAAR fellow and professor of geology, published a new study documenting how rock glaciers form. According to their analysis, the main ingredients are snow and a protective layer of rocky debris, usually provided by a tall, erosion-prone cliff overhead. Importantly, there can’t be too much ice and snow.

“The speed at which the ice moves away from the base of the cliff is governed by how thick the ice is. The thicker it is, the faster it goes,” Robert Anderson explained. “It can’t be too thick. So, avalanche run-outs are sort of the magic zone for the top of a rock glacier.”

A gap in geologic history

The Andersons’ new model of rock glacier formation led to a second insight — one about the past. According to the study, the rock glaciers we see in the Colorado Rockies today likely formed hundreds, or even thousands, of years after the big glaciers disappeared. That’s because rock glaciers actually require more temperate conditions to establish themselves.

“We argue that you lose almost all of the ice out of the alpine valleys. Then, only later, it comes back in a rock glacier mode,” Robert Anderson said.

The model is also backed by physical evidence collected by the Andersons, their students and a number of other researchers over the past three decades. To determine the age of rock glaciers, these researchers tested samples from boulders on the surface of the glaciers for a rare isotope of the element beryllium. The results indicate how long the boulder has been there, and thus how long ago the glacier formed. According to these analyses, Colorado’s rock glaciers arose around 10,000 to 12,000 years ago, which places them at least a thousand years after deglaciation.

Robert Anderson says that understanding how rock glaciers formed gives us a more clear understanding of their role in the landscape today. It might help us conserve them too.

“It’s an important part of climate history,” he said.

Rock glaciers and water

Suzanne Anderson gathers water samples from a mountain creek near the Mount Sopris rock glacier. Photo by Robert Anderson.

Today, rock glaciers are ubiquitous in Colorado’s alpine landscapes, but the role they play in mountain ecosystems is still poorly understood. According to Suzanne Anderson, the key to further understanding may lie in the unique water rock glaciers provide.

“It’s different from other water sources in the landscape for two reasons,” Suzanne Anderson explained. “It’s cold, even late in the summer, because it's coming directly from ice melt, and its chemistry is different — it’s a little more nutrient-rich.”

Some research has already suggested that certain cold-adapted insects may rely on this meltwater for survival. The Andersons and their students have also found elevated levels of nitrogen, an important nutrient for both plants and animals, in rock glacier meltwater.

One of Suzanne Anderson’s students, M.S. student Maya McDonough, is furthering these investigations. This summer, McDonogh will sample meltwater from a rock glacier near Imogene Pass, between Telluride and Ouray, Colorado and analyze its chemistry.

“We’re testing the water chemistry to see what ions are in rock glacier discharge, because those nutrients might be really important to certain high-altitude habitats,” McDonough said. “I’ll test as many samples as I possibly can.”

Rock glaciers everywhere — at least in the Colorado Rockies. New research from Robert and Suzanne Anderson investigates how they formed, and what benefits they might provide for alpine ecosystems.

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The headwall of Mount Sopris looms above a large rock glacier in the basin below. Photo by Robert Anderson.

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The headwall of Mount Sopris looms above a large rock glacier in the basin below. Photo by Robert Anderson.

American Geophysical Union’s Hydrology Section Fellows discuss the future of science

Anonymous — Thu, 22 Jun 2023 17:09:10 +0000

American Geophysical Union’s Hydrology Section Fellows discuss the future of science Anonymous (not verified) Thu, 06/22/2023 - 11:09

Michelle Werdann , U Nevada Reno

In the premier video article of the American Geophysical Union’s journal Perspectives of Earth and Space Scientists, University of Nevada, Reno Professor Emeritus Scott Tyler and marketing and communications director Jennifer Kent lead a “deep dive” into the responsibilities of earth scientists and engineers to lead and diversify the field of hydrology. What was supposed to be a casual “meet and greet” between fellows of the American Geophysical Union’s (AGU) Hydrology Section meeting in June 2022 quickly became much more. Due to ongoing challenges caused by the COVID-19 pandemic, the session was hosted online and recorded.

Tyler, the former president of the AGU’s Hydrology Section, moderated the conversation. As the conversations continued and deepened, Tyler began to recognize that they highlighted some of the pressing issues that the field and the broader scientific community face.

“It’s quite obvious and will be obvious to all those who watch this that our AGU Fellows are deep thinkers and are thinking about current issues,” Tyler said. “I think there is an evolution coming along, and I’m very proud to see that coming from…our AGU Fellows.”

The AGU is the world’s largest professional organization dedicated to earth and space science. AGU Fellowship recognizes outstanding contributions to science and constitutes only 0.1% of the Union’s membership each year.

The conversation included AGU Hydrology Fellows Suzanne Anderson (University of Colorado, Boulder), Paul Brooks (University of Utah), Aaron Packman (Northwestern University), Remko Uijlenhoet (Delft University of Technology), Andrew Western (University of Melbourne) and Xubin Zeng (University of Arizona).

Zeng spoke about the importance of innovation in research and added that scientists should share their failed ideas.

“There is no such thing as a failure, but just ideas you have tried that never worked,” Zeng said. “If we are open, if we take the lead in sharing our unsuccessful stories, that will help accelerate the science.”

The fellows spoke about issues facing the field such as the lack of socioeconomic diversity, the gains made in gender representation, the intersection between research that is impactful and interesting, and recognizing success outside of metrics like citations or academic legacy.

The video, slightly edited for time by Kent, is about one hour long. In that hour, researchers discuss the philosophies of their research and the importance of community, along with other themes. The full video is available to watch on the journal website as an open access publication.

INSTAAR Fellow Suzanne Anderson was part of a deep dive into the future of hydrologic science and the responsibilities of scientists, recorded at the inaugural Frontiers in Hydrology Meeting.

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Art and climate science converge in new exhibit at the Colorado Capitol (KUNC)

Anonymous — Wed, 24 May 2023 21:46:29 +0000

Art and climate science converge in new exhibit at the Colorado Capitol (KUNC) Anonymous (not verified) Wed, 05/24/2023 - 15:46

Emma VandenEinde

An exhibit that just opened in the Colorado capitol building's rotunda features artwork made in the process of partnerships between artists from around Colorado, their communities, and ��ϳԹ� scientists. Called “Coloradans and our Shared Environment in Times of Challenge and Change,” the art grapples with the climate and environmental challenges that are part of Coloradoans' lives: drought, decreasing groundwater, acid mine drainage, wildfire, pine beetle tree mortality, and more.

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Coloradoans and our shared environment in times of challenge and change (CU OOE)

Anonymous — Thu, 18 May 2023 18:02:12 +0000

Coloradoans and our shared environment in times of challenge and change (CU OOE) Anonymous (not verified) Thu, 05/18/2023 - 12:02

CU Office for Outreach and Engagement

A collaborative exhibition tells the story of how Coloradans are experiencing interrelated challenges of fire, drought, and water and air quality in their communities. Artists (the CASE Fellows) partnered with scientists and communities to make visible the connections between Coloradans and their environment. Several INSTAARs acted as scientist partners. This website showcases the artwork, as well as quotes from the partners, explorations of the issues, and what you can do to act.

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Announcing the Colorado Art Science Environment Fellows and Colorado State Capitol Exhibition (��ϳԹ� Community Outreach and Engagement)

Anonymous — Tue, 20 Dec 2022 00:25:19 +0000

Announcing the Colorado Art Science Environment Fellows and Colorado State Capitol Exhibition (��ϳԹ� Community Outreach and Engagement) Anonymous (not verified) Mon, 12/19/2022 - 17:25

Gretchen Minekime , CU Office for Outreach and Engagement

The Office for Outreach and Engagement announces the CASE Fellows program. The program pairs Colorado artists with ��ϳԹ� scientists to produce art that will be exhibited at the Colorado State Capitol in an exhibition about how Coloradans are experiencing interrelated challenges of fire, drought, and water and air quality. Lisa Schwartz from OOE is leading the program in partnership with Shelly Sommer at INSTAAR, Boulder County Arts Alliance and with exhibition and curatorial support from Amy Hoagland.

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New children’s book explores The Living Landscape

Anonymous — Mon, 10 Oct 2022 18:15:43 +0000

New children’s book explores The Living Landscape Anonymous (not verified) Mon, 10/10/2022 - 12:15

Shelly Sommer

A new children’s book is centered in the Critical Zone, the thin outer layer of Earth’s surface from the tops of the trees down to bedrock where life exists and interacts with rock, soil, water, and air. Designed for 8 to 12-year olds, the book is by INSTAARs Eric Parrish and Suzanne Anderson and is published by Muddy Boots Books.

The Living Landscape: Discovering the Critical Zone follows a young girl on a hike in the mountains. A fallen tree becomes a gateway for her to explore the ways air, water, plants, animals, soil, and rock cycle and affect each other. Naturalistic illustrations and informational text let readers follow her through her adventure. The story treats the landscape in an integrated way that is rare in children’s literature.

Cover of the Living Landscape

The book emerged from the Boulder Creek Critical Zone Observatory (Boulder Creek CZO), a research program that ran from 2007 through 2020 to study the critical zone from the Continental Divide to the western edge of the plains. Working with short stretches of time between other efforts and with small pieces of funding, creating the book took several years.

Parrish, an illustrator and designer, worked for the Boulder Creek CZO as a communicator. He conceived the idea for The Living Landscape and wrote a first draft in 2015. He also created all the illustrations. Anderson, an INSTAAR Fellow, Professor of Geological Sciences, and director of the Boulder Creek CZO, signed on to add scientific content.

“We were really wordsmithing, making sure that concepts were appropriate, that we had the right number of words on the page [or] appropriate vocabulary. We were tuning in concepts,” said Anderson. The goal was to bridge between scientific concepts and most people's lived experiences as they spend time outdoors.

Eric developed a new illustration style over the course of working on the book. “I transitioned from traditional media—oil and watercolor—to digital painting,” said Parrish. “I entered a 100 illustrations in 100 days challenge during COVID, and I made a jump at illustration number 50 to digital.”

The new techniques helped Parrish rework his illustrations to show the details of the natural environment. “Being part of the Critical Zone Observatory, I know the nuance. I got to study dirt,” said Parrish. “It definitely has variations in color and sedimentary layers. Showing that is all about light and texture and artistic tools.”

“I think my favorite page is the one about cycles,” said Anderson. “I love Eric’s graphic that connects the water cycle—which is taught widely—to the carbon cycle and plants, and this all connects to this big, slowly-turning rock cycle. This is how soil is made, at the interface between hydrosphere (water cycle) and lithosphere (rock cycle).”

It’s important to understand how connected everything is. We all think we’re separate, but we’re not.
--- Eric Parrish

The search for an agent or publisher took years, and eventually ended at the door of Muddy Boots, an imprint of Globe Pequot, the trade division of Rowman & Littlefield. Ironically, a previous incarnation of Muddy Boots had published a series of children’s books from the Long-Term Ecological Research program, including some with INSTAAR ties: the My Water Comes from the Mountains series and The Lost Seal. “They understand science,” said Anderson.

In the meantime, the Boulder Creek CZO program concluded and was succeeded by the Critical Zone Network in 2020. The Dynamic Water Cluster, part of the Critical Zone Network led by Holly Barnard, is supporting The Living Landscape as part of its public engagement activities.

While the book isn’t specific to a particular landscape, Colorado readers may recognize scenes from Rocky Mountain National Park, Elk Meadow, and Gordon Gulch.

Example pages of the Living Landscape

The book is designed for 8 to 12-year olds. “They’re at an age where they’re asking questions about how things work and connections between things,” said Anderson. She added, “We still have questions too.”

“When I came into the CZO, I didn’t think I’d ever love the Critical Zone,” said Parrish. But the principles of connection soon had him hooked. “It’s important to understand how connected everything is. We all think we’re separate, but we’re not.”

Parrish said, “The underlying message of my projects—if I am successful anyway—is all things are connected. Life, love and caring for our world and each other.”

The Living Landscape is available wherever books are sold, including Rowman & Littlefield, Tattered Cover, Barnes & Noble, Amazon, and local retailers.

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Anderson S

Beneath crumbling walls: how rock glaciers took over the southern rockies

A gap in geologic history

Rock glaciers and water

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American Geophysical Union’s Hydrology Section Fellows discuss the future of science

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Art and climate science converge in new exhibit at the Colorado Capitol (KUNC)

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Coloradoans and our shared environment in times of challenge and change (CU OOE)

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Announcing the Colorado Art Science Environment Fellows and Colorado State Capitol Exhibition (���ϳԹ� Community Outreach and Engagement)

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New children’s book explores The Living Landscape

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Announcing the Colorado Art Science Environment Fellows and Colorado State Capitol Exhibition (��ϳԹ� Community Outreach and Engagement)