Research

How do you measure snow from space? First, climb a mountain (New York Times)

Gabe Allen — Tue, 24 Mar 2026 14:59:08 +0000

How do you measure snow from space? First, climb a mountain (New York Times) Gabe Allen Tue, 03/24/2026 - 08:59

New York Times journalists followed the mountain hydrology lab on recent a winter excursion to Niwot Ridge. The researchers were measuring snow on the landscape in real time in order to calibrate data from an overhead satellite.

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Why pristine mountain lakes are suddenly turning green (Scientific American)

Gabe Allen — Tue, 17 Mar 2026 21:14:20 +0000

Why pristine mountain lakes are suddenly turning green (Scientific American) Gabe Allen Tue, 03/17/2026 - 15:14

Journalist Cody Cottier tells the story of the Oleksy lab's summer expedition to an alpine lake in the San Juan range. The scientists are investigating the source of a mysterious algal bloom that was first spotted by a ranger in 2021.

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A new investigation will evaluate water filtration options in a community plagued by PFAS

Gabe Allen — Wed, 11 Mar 2026 12:00:00 +0000

A new investigation will evaluate water filtration options in a community plagued by PFAS Gabe Allen Wed, 03/11/2026 - 06:00

Gabe Allen

If you are a resident of Airway Heights interested in becoming a research participant, you can visit this link for more information.

INSTAAR fellow Riley Mulhern is launching a new study to evaluate the efficacy of home treatment options for PFAS in a contaminated area outside of Spokane, Washington. (courtesy photo)

INSTAAR fellow and 91��ý professor Riley Mulhern first visited Airway Heights, Washington in January of last year. After the trip, he summed up the emotional state of the community in a one-word title to a post on his Substack: “Incensed.”

Mulhern has spent his career fighting for people's access to clean water, through both research and advocacy, and this community was in the midst of a water crisis.

A filtration system guards an Airway Heights home from contaminants. (courtesy photo)

In 2017, the city of Airway Heights found PFAS, a toxic family of industrial compounds also known as forever chemicals, in their municipal water. The contamination stemmed from firefighting foam used in training exercises at a nearby airforce base over decades. A 2022 report by federal agencies subsequently found that many residents of Airway Heights had elevated levels of PFAS in their blood — up to 56 times the national average.

Airway Heights municipal water has since been cleaned up, but many local residents own private wells. They are left to figure out how to test and filter the water that comes into their homes on their own, and many are concerned by a dearth of clear information about how to accomplish these tasks.

“One in seven Americans gets no protection from the federal Safe Drinking Water Act, we’re on our own,” said John Hancock, an Airway Heights local and president of West Plains Water Coalition, a community action group formed around the PFAS issue.

This problem is at the center of a new investigation, funded by the Water Quality Research Foundation and led by Mulhern. The study will evaluate commercially available water filtration systems’ efficacy against PFAS contamination.

“There’s a lot of confusing information online about what’s the best way to filter water, how well do these filters work, how are they certified, and so on,” Mulhern said. “So there’s a lot of value in providing third-party evidence of the real world performance of these products.”

First, Mulhern and his collaborators will test the water coming out of pre-existing home filtration systems in Airway Heights. Then, they will install filtration systems at the homes of a second cohort of participants, and monitor their water over two years.

Many filters are already certified by third-party assessors for efficacy against specific PFAS chemicals, such as PFOS and PFOA, which are currently regulated by the EPA. Yet, many more PFAS compounds are unregulated by federal drinking water standards or have not yet been included in third-party certification testing and have unknown health consequences. With this in mind, the new study will test for a broad range of PFAS and other fluorinated organic compounds which make up the larger “class” of chemicals to which PFAS belong.

“We are essentially trying to future-proof the public health recommendations we can make around household filter use,” Mulhern told the Water Quality Research Foundation. “Measuring the broader category of organic fluorine through household filters will provide increased confidence in these products for handling PFAS as a class, rather than just for specific types.”

When Mulhern first visited Airway Heights, he came as a volunteer. He spoke about water filtration options at a meeting organized by West Plains Water Coalition, drawing on his experiences working in North Carolina communities affected by PFAS. Now, he is happy to return with the necessary funding to offer more substantive support.

“We won the award because we have a strong foundation with the community already,” Mulhern said. “Even more important than that is that there is a community group that is so well organized and ready and willing to participate in research like this.”

A map illustrates data on water quality around Airway Heights, Washington. X's mark PFAS source sites, while orange dots mark private wells at risk. (courtesy photo)

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

INSTAAR fellow Riley Mulhern is launching a new study to evaluate the efficacy of home treatment options for PFAS in a contaminated area outside of Spokane, Washington.

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New minor spans disciplines in studying climate science (Colorado Arts & Sciences Magazine)

Gabe Allen — Wed, 25 Feb 2026 00:12:27 +0000

New minor spans disciplines in studying climate science (Colorado Arts & Sciences Magazine) Gabe Allen Tue, 02/24/2026 - 17:12

The interdisciplinary climate science minor, available in Fall 2026, will offer undergraduates a window into 91��ý's world class climate research. INSTAAR fellows Bradley Markle and Robert Anderson make the case for the new program.

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Inaugural Sustainability Research Initiative Research Fellows unveiled (RIO)

Gabe Allen — Mon, 23 Feb 2026 18:42:15 +0000

Inaugural Sustainability Research Initiative Research Fellows unveiled (RIO) Gabe Allen Mon, 02/23/2026 - 11:42

INSTAAR fellows Keith Musselman and Irina Overeem have been named to the inaugural cohort of SRI fellows at 91��ý. The fellows will form a year-long sustainability research incubator across academic disciplines.

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Tahoe avalanche: What causes snow slopes to collapse? A physicist and skier explains, with tips for surviving (The Conversation)

David J Lubinski — Thu, 19 Feb 2026 04:13:09 +0000

Tahoe avalanche: What causes snow slopes to collapse? A physicist and skier explains, with tips for surviving (The Conversation) David J Lubinski Wed, 02/18/2026 - 21:13

Nathalie Vriend updated an article for The Conversation that explains what happens in an avalanche, techniques for surviving one, and how they are impacted by climate change.

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'Hiding in plain sight': Scientists reflect on years studying life in Antarctic desert (91��ý Today)

David J Lubinski — Wed, 11 Feb 2026 23:48:47 +0000

'Hiding in plain sight': Scientists reflect on years studying life in Antarctic desert (91��ý Today) David J Lubinski Wed, 02/11/2026 - 16:48

Researchers at the McMurdo Dry Valleys Long-Term Ecological Research Program have spent more than three decades studying ecosystems in one of the world’s most hostile environments. Diane McKnight and Mike Gooseff discuss the importance of the research, its challenges, and its rewards.

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Some tropical land may experience stronger-than-expected warming under climate change (91��ý Today)

David J Lubinski — Wed, 04 Feb 2026 23:03:58 +0000

Some tropical land may experience stronger-than-expected warming under climate change (91��ý Today) David J Lubinski Wed, 02/04/2026 - 16:03

Lina Pérez-Angel and Julio Sepúlveda led a team to study a sediment record millions of years old from the tropical Andes. They found that the region heated up dramatically when atmospheric CO2 levels were similar to today’s.

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Breaking ice, moving earth: Greenland will release more sediment into the ocean as the climate warms

Gabe Allen — Mon, 02 Feb 2026 13:00:00 +0000

Breaking ice, moving earth: Greenland will release more sediment into the ocean as the climate warms Gabe Allen Mon, 02/02/2026 - 06:00

Gabe Allen

Ethan Pierce aboard the Porshild, the research vessel of the Arctic Research Station in Disko, Greenland. (Irina Overeem)

Greenland’s winding, rocky fjords are no strangers to research vessels. Usually, these boats give icebergs a wide berth, because they can roll over unexpectedly.

That wasn’t the case, though, for the boats carrying INSTAAR fellow and CU associate professor Irina Overeem and her former PhD student Ethan Pierce during the 2019 and 2022 summer field seasons. They were there for the icebergs.

Relying on the caution and expertise of Greenlander captains, the scientists sidled up to the floating monoliths aboard small dinghies and carefully chipped off samples before returning to the main boat.

A small dinghy carries Irina Overeem, Tom Marchitto, and Mia, a Greenlandic deckhand, out to sample an iceberg. (Nora Matell)

“We really were relying on the Greenlanders a lot for their sense of what was safe and what was not,” Pierce said.

“They fish in that environment themselves, so they have a ton of experience doing that risk calculation,” Overeem added.

Five years later, that calculated risk is paying off. Pierce, Overeem and University of Copenhagen associate professor emeritus Bent Hasholt published a new paper in Nature Communications documenting how icebergs bring sediment from Greenland out to sea.

Tom Marchitto paddles a packraft out to sample a dirty iceberg in Nuup Kangerlua (Irina Overeem)

The investigation is the first to unravel the complex process underlying a phenomenon that has an outsized impact on the Arctic Ocean’s chemistry. The scientists estimate that icebergs account for around one third of all of the sediment leaving Greenland (the rest comes from meltwater). That sediment unloads nutrients into Arctic waters, which support organisms at every scale — from phytoplankton to whales.

Irina Overeem poses with her catch in a Greenlandic fjord. (Tom Marchitto)

Importantly, the scientists were also able to determine the effect of climate change on this process. As the planet warms, icebergs will deposit more and more sediment into the ocean.

“This is the first modern study of this process that can say, ‘with a warming climate we’re going to see more transport of ice-rafted debris,’” Pierce said.

A back-of-the-envelope calculation

Greenland contributes around 15 percent of the sediment that ends up in the ocean each year — an exceptionally high figure for a landmass of its size. Nearly a decade ago, Overeem published another paper characterizing the amount of sediment coming from Greenlandic meltwater rivers. She found that these waterways were unloading a vast amount, but they didn’t account for all of Greenland's sediment export.

At the time, Overeem already knew that icebergs might be the missing piece of the puzzle. For years, she had seen dark stripes of debris crisscrossing icebergs in Greenlandic fjords. And, ice-derived debris has long been found in sediment cores pulled from the bottom of the Atlantic Ocean. But, scientists had yet to figure out how exactly the debris got in the ice or how much of it left the continent this way.

On the flight home from her 2016 field season, Overeem started jotting down rough equations based on previous research from colleagues. The numbers shocked her.

“At the time, I did a back-of-the-envelope calculation,” she said. “I was shocked at how much it could be.” “I pitched the idea to the CU Research and Innovation Office and they funded a pilot project.”

By 2019, Overeem brought Pierce on as a PhD student and put him on the project. Unfortunately, the pandemic delayed multiple field seasons, but Pierce used the extra time to drill down on a mathematical model of how the debris ends up in the ice in the first place.

According to Pierce’s model, the weight of the massive Greenland ice sheet creates pressure points where the ice comes into contact with individual grains of sand on the earth below. These pressure points create heat, which melts the ice. The meltwater then refreezes around the grain of sand. As the ice sheet slides downhill toward the ocean, this process sucks up more and more sediment into the bottom layer of ice. Eventually, the ice reaches the waters edge and breaks off, forming a sediment-laden ice berg.

Pierce's model combined with the field sample data produce the central insight of the new paper — that icebergs contribute about one third of Greenland’s sediment export.

“There are lab experiments and grain-scale models that show that these processes happen, but Ethan is the first person who put together a numerical model that can then be extrapolated out on the scale of the Greenland ice sheet,” Overeem said.

Powering new research

Now that Overeem’s back-of-the-envelope calculation has grown into a sophisticated model, it’s time for the researchers to pass their data on to other scientists. The model could be useful for myriad other projects, including offering hints into ancient climatic conditions.

Another potential application is more forward looking. As sediment in the Arctic Ocean increases, it will increase the abundance of minerals like iron and silicon. Those are minerals used by phytoplankton, the microscopic foundation of the Arctic marine food web.

“People who are good at observing phytoplankton over the long-term record have seen an uptick in Greenland,” Overeem said. “There’s definitely some interest in this from that community.”

It’s not yet clear exactly how an increase in sediment might affect life in the ocean, but the question could spark further collaborations within the Institute of Arctic and Alpine Research. Tom Marchitto’s laboratory excels at precise measurements of dissolved chemicals, a capability that could further resolve the contents of Greenlandic sediment. On the biological side of things, INSTAAR director Nicole Lovenduski’s lab specializes in modeling phytoplankton blooms in the Arctic.

“This is just one part of a number of potential connections,” Overeem said.

For now, Pierce will move onto other projects as a postdoctoral researcher at Dartmouth, and Overeem will turn her attention to other pressing surface process models. Both can rest easy knowing they placed another puzzle piece in the answer to a question that has loomed over generations of Greenlandic science.

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

A new paper from Irina Overeem and Ethan Pierce describes how icebergs export Greenlandic sediment into the Arctic Ocean — and how that process might change in the future.

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An iceberg sheds sediment as it melts into Torsukattak Fjord in Greenland. (Irina Overeem)

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Research highlight: Dr. Keith Musselman and the EcoTram (MRS News)

Gabe Allen — Wed, 14 Jan 2026 16:53:42 +0000

Research highlight: Dr. Keith Musselman and the EcoTram (MRS News) Gabe Allen Wed, 01/14/2026 - 09:53

INSTAAR fellow Keith Musselman and collaborators have constructed an "EcoTram" that continuously measures hydrological and ecological variables across a 400-foot transect high in the Indian Peaks. The system provides a wealth of data for investigations into shifting mountain systems.

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Research

How do you measure snow from space? First, climb a mountain (New York Times)

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Why pristine mountain lakes are suddenly turning green (Scientific American)

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A new investigation will evaluate water filtration options in a community plagued by PFAS

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New minor spans disciplines in studying climate science (Colorado Arts & Sciences Magazine)

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Inaugural Sustainability Research Initiative Research Fellows unveiled (RIO)

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Tahoe avalanche: What causes snow slopes to collapse? A physicist and skier explains, with tips for surviving (The Conversation)

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'Hiding in plain sight': Scientists reflect on years studying life in Antarctic desert (91��ý Today)

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Breaking ice, moving earth: Greenland will release more sediment into the ocean as the climate warms

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Research highlight: Dr. Keith Musselman and the EcoTram (MRS News)

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