Mount Spurr Volcano Alert: Anchorage Prepares for Possible Eruption

Nearly 300,000 people in Anchorage, Alaska, are on high alert as Mount Spurr, a massive volcano just 80 miles away, shows signs it might erupt soon. Scientists at the Alaska Volcano Observatory (AVO) have reported thousands of earthquakes, gas emissions, and other clues that magma is moving underground. Residents are stocking up on masks, goggles, and even pet gear to protect against ashfall. Here’s everything you need to know about Mount Spurr’s unrest, what an eruption could mean, and how Anchorage is getting ready, written in simple language.

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Why Mount Spurr Is a Concern

Mount Spurr is a towering volcano, standing at 11,070 feet, almost 2,000 feet taller than the Yellowstone supervolcano. It’s located in southcentral Alaska, close enough that on clear days, Anchorage residents can see its snowy peak in the distance. Anchorage, Alaska’s largest city, is home to nearly 300,000 people, making it a major hub for the state. Because the volcano is so close—just 80 miles west—any eruption could affect the city, its airport, and nearby communities.Alaska Volcano Observatory/Alaska Division of Geological & Geophysical Surveys

Alaska has about 169 active volcanoes, and the AVO keeps an eye on around 90 of them. Mount Spurr is one of the most watched because it has erupted before, in 1953 and 1992. Those eruptions sent ash falling on Anchorage, causing problems like airport closures and health risks. Now, with new signs of activity, scientists and residents are preparing for what might happen next.

Earthquake Swarms Signal

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Since April 2024, Mount Spurr has been shaking with thousands of small earthquakes. These quakes are a sign that magma, or molten rock, might be moving closer to the surface, putting stress on the rocks and causing them to crack. Here’s what the AVO has found:

• Over 3,400 earthquakes have been recorded near Mount Spurr since April 2024.
• From February to March 2025, there were more than 100 quakes per week, with some weeks seeing even higher numbers.
• Most quakes are tiny, with magnitudes under 1, but a few have been stronger, like a 2.2-magnitude quake on April 13, 2025, at 7:43 PM ET, and a 3.7-magnitude quake near Petersville, 30 miles northwest of Spurr, on April 2, 2025.
• In early October 2024, the quake rate jumped from 30 per week to 125 per week, and it’s stayed high since then.

Matt Haney, the AVO’s lead scientist, told DailyMail.com that these quakes show the volcano is restless. “The swarms suggest pressure is building, cracks are widening, and magma is moving,” he said. While most quakes are too small to feel in Anchorage, they’re a warning that something’s happening underground.

Other Signs of Unrest

Hannah Dietterich/Alaska Volcano Observatory

Earthquakes aren’t the only clue Mount Spurr is active. Scientists have noticed other changes that point to a possible eruption:

• Gas emissions: On March 7, 2025, AVO flights measured high levels of sulfur dioxide and carbon dioxide coming from the volcano. These gases dropped by mid-March, which could mean magma has hardened, trapping gas and adding pressure underground.
• Ground swelling: The volcano’s surface has shifted slightly, showing magma or gas is pushing up from below.
• Steam plumes: On March 26, 2025, a large steam cloud was seen rising from the summit. This could be caused by heat melting snow or ice inside the crater.
• Crater lake: A small lake formed in the summit crater in summer 2024, likely from melting ice. It’s grown slightly, suggesting heat is coming from underground.

The AVO’s Monday update on April 14, 2025, noted that while seismicity remains high, no new steaming was seen on land cameras, and cloudy weather blocked satellite views. These signs don’t guarantee an eruption, but they make it more likely than usual.

What Would an Eruption Look Like

Ernest Tyler/Co-Op Photo Shop via Alaska Volcano Observatory

If Mount Spurr erupts, scientists expect it to be similar to what happened in 1953 and 1992. Here’s how those events played out:

• 1992 Eruptions: Mount Spurr erupted three times—June, August, and September. The August eruption was the worst for Anchorage, dropping about an eighth of an inch of ash on the city. The ash cloud reached 12 miles high, darkened the sky, and forced the airport to close for 20 hours. Cleanup cost Anchorage nearly $2 million, and two people had heart attacks (one fatal) while shoveling ash.
• 1953 Eruption: This eruption covered Anchorage with a quarter-inch of ash, causing similar disruptions but less damage.

Haney explained that a new eruption would likely be explosive, sending ash plumes as high as 50,000 feet. “Each explosive burst could last three to four hours,” he told DailyMail.com. “Ash would spread hundreds of miles, depending on the wind.” In Anchorage, residents might not hear the eruption, but closer to the volcano, it could sound like thunder from volcanic lightning caused by ash particles rubbing together.

The AVO predicts a quarter-inch of ash could fall on Anchorage, enough to cause problems but not destroy the city. A larger eruption is possible but rare, as the geologic record shows they haven’t happened in recent history.

Where Would It Erupt?

Susan Walker

Mount Spurr has two main spots where an eruption could happen:

• Crater Peak: This side vent, about 2 miles south of the summit, erupted in 1953 and 1992. It’s the most likely spot because it’s more open, needing less pressure to release magma.
• Summit Crater: The main crater hasn’t erupted in about 5,000 years, so it’s less likely. It would take a lot more force to break through the blocked summit.

Haney said Crater Peak is the focus right now, as most earthquakes and gas emissions are happening near it

Why Is This Happening?

Alaska sits on the “Ring of Fire,” a zone around the Pacific Ocean where tectonic plates collide. The Pacific plate is sliding under the North American plate, creating magma that fuels volcanoes like Mount Spurr. This process, called subduction, is why Alaska has so many active volcanoes. Mount Spurr’s Crater Peak is especially active because past eruptions have cleared a path for magma to reach the surface more easily.

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The recent quakes, gas, and ground changes suggest magma is rising, but it’s not clear how close it is to erupting. The drop in gas emissions by mid-March 2025 could mean a blockage is forming, trapping pressure, or it could mean the volcano is calming down. Scientists aren’t sure yet.

How Anchorage Is Preparing

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With warnings from the AVO, Anchorage residents are taking no chances. On March 20, 2025, the city raised its emergency planning to Level 2, meaning officials are sharing more updates and preparing response plans. Here’s what people are doing:

• Stocking supplies: Residents are buying N95 masks, goggles, latex gloves, gas masks, and jugs of water to protect against ash and ensure they have essentials if supplies are delayed.
• Protecting pets: Many are getting goggles, booties, and even respirators for their dogs and cats. A local pet store, AK Bark, sold over 500 pairs of dog goggles in March 2025 and has 1,800 dog respirators on order.
• Sealing homes: Some are stockpiling duct tape to seal windows and doors, though others, like TikToker Lia, say their homes are already well-sealed.
• Emergency plans: Schools have plans to shelter students if ash falls during the day, and officials are checking on people with asthma or heart issues.

Lia, a TikToker from Anchorage, shared a video showing her family’s preparations. “Mount Spurr is about to erupt, and we’ve never been through this before,” she said. She bought respirators, swim goggles to keep ash out of her eyes, vehicle air filters, and dog goggles for her pup. “We’re ready for about a quarter-inch of ash,” she added, explaining that’s what experts predict.

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Another resident, Angela Łot’oydaatlno Gonzalez, posted a TikTok showing her dogs in goggles. “They’re not thrilled, but we’ve got masks, booties, tape, and water ready,” she said. Anchorage locals Alliana Salanguit and Jesslin Wooliver told NPR they got heart-shaped pink goggles for their dog, Iroh, as soon as warnings came out. “They’re darling!” Salanguit said.

Pet Safety Tips

The city has shared advice for pet owners to keep animals safe:

• Keep pets inside as much as possible to avoid ash exposure.
• Stock up on two weeks of food, water, and medicine for pets.
• Clean ash off fur by brushing or washing if pets go outside.
• Use protective gear like goggles and booties to shield pets’ eyes and paws.

AK Bark’s owner, Mark Robokoff, told NPR the demand for pet gear has been huge. Locals are even sharing photos of their dogs in goggles on the store’s Facebook page, showing how seriously they’re taking the threat.

Health Risks of Volcanic Ash

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The International Volcanic Health Hazard Network (IVHHN) warns that volcanic ash is dangerous, especially for people with health issues. Here’s why:

• Lung problems: Ash is sharp and can irritate lungs, worsening asthma or causing breathing trouble.
• Eye and throat irritation: Ash can make eyes red, itchy, or sore and cause coughing or sore throats.
• Heart risks: Shoveling ash, like during the 1992 eruption, led to heart attacks for two Anchorage residents.

N95 masks are recommended because they block tiny ash particles better than cloth masks. Goggles and staying indoors can protect eyes and skin.

Could It Not Erupt?

There’s a chance Mount Spurr won’t erupt. In 2004-2006 and 2012, it showed similar unrest—quakes, gas, and a crater lake—but calmed down without erupting. Haney said, “It’s possible the magma could stall, and the activity could fade.” The drop in gas emissions in March 2025 might mean the volcano is settling, but the ongoing quakes suggest it’s still active.

Scientists estimate a 50-50 chance of an eruption in the next few weeks or months. If they detect a volcanic tremor—a steady shaking caused by magma moving fast—it would be a strong sign an eruption is near. For now, the volcano is at a yellow/advisory alert level, meaning it’s restless but not erupting yet.

How Scientists Are Watching

The AVO is using advanced tools to monitor Mount Spurr:

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• Seismic sensors: These detect quakes, with over 3,400 recorded since April 2024.
• Gas flights: Planes measure sulfur dioxide and carbon dioxide, like the high levels found on March 7, 2025.
• Ground sensors: GPS devices track ground swelling, which shows magma or gas pressure.
• Cameras and satellites: Webcams and satellites look for steam or crater changes, though clouds blocked views on April 14, 2025.
• Overflights: Scientists fly over to check for steaming, fumaroles (gas vents), or lake growth.

The AVO updates the public daily, and Anchorage residents can sign up for alerts by texting ANCHORAGE to 67283 or visiting avo.alaska.edu.

Looking Ahead

Mount Spurr’s unrest has Anchorage on edge. With over 3,400 quakes since April 2024, high gas levels in early March, and steady seismic activity, an eruption is possible—maybe soon. But it’s not certain, and the volcano could quiet down, as it has before. The AVO is watching closely, and if they see signs like volcanic tremor, they’ll raise the alert to orange/watch or red/warning.

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For now, residents are preparing for the worst while hoping for the best. From buying N95 masks and dog goggles to sealing homes and stocking water, Anchorage is ready to face ashfall if it comes. The city’s Level 2 emergency status ensures officials are planning, and schools and agencies are set to act if needed.

Mount Spurr reminds us how powerful nature is. Its last eruption was 33 years ago, and while no one wants a repeat, being prepared can keep everyone safe. Stay tuned to AVO updates, and if you’re in Anchorage, keep those supplies handy. Whether it erupts or not, the city’s response shows how Alaskans come together in tough times.