A massive cloud of dark ash rising 50,000 feet high in the air, casting a city in darkness during daylight and covering it with a suffocating layer of dust.

This is what happened the last time Mount Spurr, an 11,000-foot-tall volcano in Alaska, erupted in 1992.  

Now, experts say it is poised to blow again. 

Mount Spurr has been showing signs of unrest for more than a year, with scientists fearing an eruption is imminent.

There has been heightened activity over the past few months, including numerous small earthquakes, ground deformation, and gas and steam emissions. 

Mount Spurr sits just 81 miles from Alaska’s most densely populated city, Anchorage, which is home to nearly 300,000 residents.

According to Matt Haney, the lead scientist at the AVO, if the volcano erupts, the event would be highly explosive. He mentioned that the eruption might resemble the one that occurred at Mount Spurr on August 18, 1992.

A resurfaced video from that day shows an enormous black cloud of ash billowing out of Mount Spurr’s side vent, Crater Peak.

This cloud, or ‘eruption column’ stretched 50,000 feet into the sky, and was captured by AVO scientists who dared to fly a plane around it. 

The ash eventually reached Anchorage, where it dimmed the daylight and forced the closure of all local airports as it settled an eighth of an inch thick across the entire city.

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

The Municipality of Anchorage reported nearly $2million in damages, office closures and cleanup costs from the August eruption.

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 video of the 1992 eruption column aired on Alaska’s News Source in March. 

In addition to this huge plume of ash and gas, a Mount Spurr eruption could also produce destructive mudslides and avalanches of volcanic debris that race down the volcano’s sides at over 200 miles per hour.

‘But fortunately, there are not any communities in that radius that would be affected,’ Haney said. 

In response to the volcano’s heightened activity, Anchorage officials raised the emergency planning level to Level 2 on March 20.   

This means that they will ramp up communication with the public about the threat and public safety agencies will prepare to launch into eruption response protocols. 

Residents are already disaster-prepping, stocking up on N9-5 masks, latex gloves and jugs of water, along with protective goggles, gas masks and booties for their dogs.

‘We’re getting ready for the volcanic eruption,’ said TikTok user Angela Łot’oydaatlno Gonzalez in a recent video, ‘Check out the dogs.’

Wearing a pair of goggles, she sits with her two dogs who are also sporting protective eyewear. ‘They’re not happy with the goggles,’ Gonzalez says. ‘We have to get them ear protection next, and something to cover their bodies.’

Gonzales is far from the only one making sure she and her pets will be safe.

Anchorage residents Alliana Salanguit and Jesslin Wooliver told NPR that they bought protective gear for their dog, Iroh, as soon as scientists announced that Mount Spurr may erupt. 

‘I searched ‘pink, dog goggles, small,’ and it was the top result,’ Salanguit said of Iroh’s heart-shaped goggles. ‘Aren’t they darling?’ 

The city has also issued safety recommendations for pet owners ahead of the possible eruption.

Officials advised people to keep their animals inside as much as possible, have enough food and medication on hand to last two weeks, and be sure to brush or wash ash out of their fur if they do have to go outside. 

The AVO has been monitoring unrest at Mount Spurr since April 2024, when it started shuddering with small earthquakes — the first clue that new magma was rising toward the volcano’s vents. 

In October, the rate of quakes around the volcano increased from an average of 30 per week to 125 per week. 

In recent weeks, the AVO has detected gas and steam emissions from Mount Spurr, though these have primarily occurred at its summit crater which hasn’t erupted in about 5,000 years.

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 June 1992 — the last time Mount Spurr erupted — volcanic tremors began about three weeks before it finally blew.