Long-Dormant National Park Volcano Begins to Stir In Part of Worrisome Global Trend

New activity raises questions about what happens when ancient ice no longer holds the planet’s fire in place.

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Jul 12, 2025

In a break from our ongoing reporting covering the figurative cataclysmic rumblings emanating from our nation’s capital let’s talk about some literal volcanic activity that’s happening in one of our largest national parks.

A glacier-cloaked volcano inside one of America’s most remote national parks has begun to stir.

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Iliamna Volcano, nestled in Alaska’s Lake Clark National Park and Preserve, hasn’t erupted since 1867. For more than a century, it’s remained a quiet white peak above the Cook Inlet – occasionally venting vapor, occasionally triggering ice-fed avalanches, but largely left alone.

Then, on June 15, something shifted. Seismic monitors registered a nearly continuous flurry of shaking. It wasn’t just the usual icefall or isolated tremor. Scientists with the Alaska Volcano Observatory called it a “ramp-up” in activity. NASA put it bluntly: the volcano is “ready to rumble.”

At first glance, the threat may seem local - another icy mountain far from the headlines, quietly monitored by volcanologists. But what’s happening at Iliamna may be part of something much bigger. Around the world, volcanoes once sealed under thick glaciers are beginning to move again in inconvenient places.

And scientists are warning - as the ice retreats, the Earth is waking up.

A Quick Book Rec!

A quick aside - I’ve got a great book rec for folks interested in exploring more of California’s more off the beaten path destinations.

Josh Jackson

, the writer and photographer behind the Forgotten Lands Project, was kind enough to send me a copy of his new book, The Enduring Wild: A Journey into California’s Public Lands. It’s a beautiful mix of storytelling, history, and photography focused on BLM-managed lands across the state. I love it and highly recommend it for anyone curious about the overlooked corners of California’s public lands and why they’re worth protecting.

A Story of Fire and Ice

A new study presented this year at the Goldschmidt Conference in Prague, led by Pablo Moreno-Yaeger of the University of Wisconsin-Madison, found that melting glaciers can trigger dormant volcanoes to erupt more frequently and explosively. The research, based in the Chilean Andes, adds hard evidence to a growing theory: ice holds volcanoes in check. Remove that weight, and the balance is lost.

Volcanoes don’t just erupt because they feel like it. They erupt because pressure builds, gas escapes, and something deep underground shifts. But what happens aboveground matters too. Especially when what’s above is thousands of feet of ancient ice.

Glaciers aren’t passive scenery. For volcanoes like Iliamna, they act as a cap. The sheer weight of the ice applies pressure that keeps magma chambers stable, gases compressed, and tectonic stress subdued. When that weight begins to melt away, the equilibrium falters. Gases expand. Cracks form. Magma rises.

It’s a pattern scientists have watched before. And one they are seeing again now, more often, in places where ice is vanishing faster than at any point in recorded history.

For Iliamna, that glacial lid has thinned. Warming has gnawed into the Chigmit Range’s permanent snowpack. Avalanches are more frequent. Rock is destabilizing. What was once an ice-sealed system is starting to breathe again.

This isn’t an isolated curiosity. The connection between retreating glaciers and volcanic reawakening is becoming clearer with each new tremor. And the implications stretch far beyond Alaska.

The Chilean Clue

In southern Chile, scientists dug into the past to understand the future. Moreno-Yaeger’s team focused on six volcanoes in the windswept Andes, including the long-quiet Mocho-Choshuenco. By dating crystals inside volcanic rock and cross-referencing those eruptions with glacial coverage, they uncovered a clear pattern: when the glaciers grew thick, the volcanoes went quiet. When the ice melted, eruptions followed.

The key isn’t just heat. It’s pressure. During the last ice age, the Patagonian Ice Sheet sat like a concrete slab atop these peaks, holding volcanic activity in check. It suppressed eruptions by containing gas buildup inside the magma chambers, preventing pressure from reaching a breaking point. But when the ice retreated - suddenly and sharply - everything changed.

Trapped magma began to rise. Pressure built. Volcanoes that had remained dormant for tens of thousands of years erupted in bursts. The silence, it turns out, had never been peace. It was restraint.

This wasn’t just a slow natural cycle. It was an explosive release triggered by a rapid loss of surface pressure. And as Moreno-Yaeger warns, the same conditions are being recreated now in places like Antarctica, Alaska, and the Pacific Northwest.

The Chilean findings confirm what volcanologists have suspected since similar effects were observed in Iceland. But this study broadens the risk far beyond one island nation. It suggests that anywhere glaciers are melting over dormant volcanoes, the potential for eruption is no longer theoretical. It’s historical. It’s geological. It’s underway.

The Worst of This Climate Problem Isn’t in America (For Once)

The pattern emerging in Alaska, Chile, and Antarctica is not isolated. It’s global. From Russia’s Kamchatka Peninsula to New Zealand’s Southern Alps, the same conditions are forming in mountain ranges shaped by fire and locked in place by ice.

In Iceland, the link between deglaciation and volcanic activity was documented decades ago. There, eruptions spiked as glaciers receded following the end of the last ice age. The crust rebounded. The pressure changed. Magma moved.

Now, that same rebounding is happening elsewhere. In North America, the Cascade Range in the Pacific Northwest - home to Mount Rainier, Mount Hood, and Mount St. Helens - sits beneath shrinking glaciers and thinning snowfields. Some of the largest glacial ice loss in the Lower 48 is occurring on the flanks of active volcanoes.

In Kamchatka, one of the most volcanically active regions on Earth, permafrost and glacial ice are retreating at record pace. The same is true in the Aleutian Islands, which are part of the same fault system as Iliamna. As the pressure lifts, volcanologists are watching for signs that once-dormant systems are entering new phases of unrest.

And in New Zealand, where the Southern Alps rise steeply from coast to sky, researchers have begun assessing glacial retreat over stratovolcanoes like Mount Ruapehu and Mount Taranaki. The results are preliminary. The warnings are not.

What unites these landscapes is not just tectonic instability. It’s a shared vulnerability: glacial ice that has, for centuries, acted as a stabilizer is disappearing. And the systems beneath are responding.

The more scientists look, the more volcanoes appear not as isolated peaks, but as pressurized systems wired into the climate machine. When one part shifts - like the loss of surface ice - the rest does not stay still.

A Feedback Loop with Teeth

Volcanic eruptions don’t just reshape landscapes. They reshape atmospheres. And when they’re triggered by melting glaciers, they become part of a dangerous cycle. One that loops heat back into the system.

The classic example is Mount Pinatubo. When it erupted in 1991, it hurled so much sulfur dioxide into the stratosphere that global temperatures dipped by half a degree Celsius. But Pinatubo was the exception. Most eruptions don’t cool the planet. Most add heat.

Volcanoes release carbon dioxide and methane, two of the primary gases driving global warming. A single eruption might not tip the balance. But a series of smaller, sustained eruptions from newly destabilized systems can add up. More heat released. More ice lost. More volcanic systems pushed past the threshold. And the cycle continues.

Antarctica poses a particular risk. Eruptions under the ice would not only emit greenhouse gases but also inject heat directly into the base of the ice sheet. That heat accelerates melting from below, causing faster ice collapse and a surge of freshwater into the oceans. The result is not just rising sea levels but disruption of ocean currents that regulate climate around the world.

In the Andes, the feedback loop follows a different route. As glaciers disappear from high-elevation volcanoes, the land beneath heats more quickly. Soil dries out. Vegetation shifts. Downstream water supplies grow more unpredictable. Wildfire risk climbs. Tens of millions of people depend on these mountain systems. When the ice goes, stability goes with it.

Volcanoes are not immune to climate change. They are part of it now. As the ice retreats, they are shifting from passive features in the landscape to active forces in a system already under pressure.

The Takeaway

What’s happening at Iliamna is not just a curious blip in a remote Alaskan park. It is a signal. A mountain long thought sealed is beginning to shift. The ice above it is retreating. The system beneath it is changing.

This isn’t an isolated story. It’s the local face of a global pattern. From the Andes to Antarctica, once-dormant volcanoes are entering new territory. Not because of new magma, but because the weight that kept them quiet is disappearing.

We are used to thinking of volcanoes as unpredictable. We are less used to thinking of them as responsive. But that is exactly what they are. They respond to pressure. They respond to ice. And now, they are responding to us.

The planet remembers what we often forget – everything is connected. Climate change does not just warm the air and melt the seas. It moves the ground beneath our feet.

If this story made something click for you, share it. Most people don’t know that melting ice can trigger eruptions. More should.

Until next time,
Will