Almost 300,000 residents in Alaska's largest city are bracing for an explosive volcanic eruption.

Mount Spurr, a 11,000-foot-tall volcano that sits just 81 miles from the largest city in the state, is due to blow this year for the first time in 30 years.

City officials in Anchorage have raised the emergency planning level to Level 2, meaning that they will ramp up communication with the public about the threat and public safety agencies will prepare to launch into eruption response protocols. 

'If it's during the school day, as soon as we get word that an eruption has occurred, we're going to be reaching out to the Volcano Observatory,' said Anchorage School District Office of Emergency Management Director Jared Woody.  

'We're going to be working with the National Weather Service, as well as (the city) to find out what are the anticipated impacts to the city. Is the ash plume coming towards us at this point?' 

Scientists at the Alaska Volcano Observatory (AVO) say Mount Spurr is 'moving closer to an eruption' that could happen in 'weeks to months.'

On March 7, the volcano began releasing elevated levels of gas from its summit and a side vent that last erupted in 1992. 

These emissions are the latest development in a period of unrest this volcano has been experiencing since April 2024, when it started shuddering with small earthquakes — the first clue that new magma was rising toward the volcano's vents.  

'This escalation is simply because we know something might come and we're getting ready,' Municipal Manager Becky Windt Pearson said. 

The eruption would most likely occur at the Crater Peak side vent, and 'it would be explosive,' Matt Haney, scientist-in-charge at the Alaska Volcano Observatory (AVO) at US Geological Survey (USGS) told DailyMail.com.

This event would spew multiple plumes of ash rising as high as 50,000 feet into the air, Haney said. 

Each ash-producing explosive episode would last three to four hours, and the resulting cloud could blanket the city of Anchorage and other nearby communities in a thick layer of dust. 

The eruption would also produce destructive mudslides and avalanches volcanic debris racing down the volcano's side at over 200 miles per hour, 'but fortunately, there are not any communities in that radius that would be affected,' Haney said. 

The USGS has the volcano under 'advisory,' meaning it 'is exhibiting signs of elevated unrest.' 

In light of Mount Spurr's unrest, Anchorage School District officials have shared their plans for if it erupts. 

The first thing they will do is contact the AVO to assess the threat and determine how much time they have to act.  

'The response time really determines on how much time do we have,' said Anchorage School District Chief Operating Officer Jim Anderson. 

'If they say there's no ash coming to Anchorage, it's business as usual. We may pre-stage buses, but if they say it's coming now, we will close schools. We will inform the public. 

'The buses, we've already walked this through with transpiration, and they will start slowly getting kids home as they would a normal end of day.'

If the ash plume barreled toward Anchorage so fast that schools couldn't get kids home in time, officials have a plan for that too. 

'If it was coming so quickly that you couldn't get them home, we would move them to one of the shelter sites where we have cafeterias, we can feed them,' Anderson said. 

'They're going to have water. And then we'll inform the public. We know that some parents would come and pick up their students. But we'll have staff there to make sure that we affect the link-up.' 

District officials said every school has a volcano response plan with shelter-in-place procedures and air quality measures, and that schools will take extra precautions with students and staff who have respiratory conditions. 

The district also has 22 emergency Connex units across the school district that are filled with enough N95 masks, first-aid kits and essential supplies for any staff members, students and visitors who may be inside schools if and when the ash cloud arrives. 

An eruption from Mount Spurr will probably look similar to the one that occurred in 1992, Haney said. 

In June 1992, the Crater Peak flank vent awoke from nearly 40 years of dormancy and erupted after 10 months of elevated seismic activity, according to the USGS.

This event covered the city of Anchorage, home to nearly 300,000 people, in an eighth of an inch of ash.

The skies darkened in the middle of the day due to the enormous cloud of dust and gas, and the city's airport was forced to shut down for 20 hours.  

Crater Peak then erupted two more times, once in August and again in September. 

The Municipality of Anchorage reported nearly $2 million in damages, office closures and cleanup costs from the August eruption, according to the National Oceanic and Atmospheric Administration (NOAA). 

No one was killed by these events directly. But two heart attacks, one fatal, from shoveling ashfall were reported in Anchorage. 

Breathing in ash also poses a health hazards. The tiny particles can work their way deep into the lungs, worsening symptoms for people with respiratory conditions such as asthma or bronchitis. 

The AVO has been monitoring Mount Spurr's heightened activity for the last year. 

Between April 2024 and February 2025, Mount Spurr exhibited three key signs of a forthcoming eruption: increased seismic activity, swelling of the volcano's surface and snow and ice melt near the summit.

Last month, the AVO said the volcano's activity was equally as likely to die down as it was to lead to an eruption. 

But on March 7, scientists flew over Mount Spurr to measure the gases rising from its two vents. For the first time since the heightened activity began, they detected gas emissions that were 'above background,' Haney said. 

They flew over again on March 11 to check their measurements, and confirmed that the volcano was producing higher-than-average levels of gas.  

'With the new measurement of gas emissions above backgrounds, that led us to conclude that an eruption like the two recent ones was the most likely scenario,' Haney said.  

Mount Spurr last erupted in 1992 and 1953, and both events were produced by the Crater Peak side vent. 

Haney and his colleagues estimate that the volcano's summit crater hasn't erupted in the last 5,000 years. So when Mount Spurr blows again, it will most likely be from the side vent, he said.  

While all signs point to an eruption in the near future, it's impossible to say exactly when it will occur.

But if Mount Spurr's activity continues to ramp up, the next sign of an eruption will be a volcanic tremor, Haney said. 

This would be different from the brief, shallow earthquakes this volcano has already been experiencing.

A volcanic tremor is a longer stretch of ongoing shaking that can persist for minutes to days.

It occurs when magma beneath the volcano begins rising toward the surface as the eruption grows imminent. 

Back in 1992, Mount Spurr was rocked by a volcanic tremor about three weeks before the June eruption, so this type of seismic activity could signal that the volcano will blow in just a few weeks.

However, other volcanoes have experienced longer periods between a volcanic tremor and an eruption, such as the nearby Mount Readout.

This volcano experienced a volcanic tremors for two months before it finally blew in 2009.

While forecasting an eruption is filled with uncertainty, Haney and his colleagues will continue to closely monitor Mount Spurr to glean a rough idea of when it is most likely to erupt.