Mount Rainier is central to Tacoma’s identity, so much so that it appears on the city’s logo. But as CNN recently reported, the striking mountain is also an active volcano — and no one knows when it will blow.
CNN briefly mentioned Tacoma in its June article, “Why Mount Rainier is the US volcano that troubles scientists most.” One expert told that outlet the volcano “keeps [her] up at night.”
To learn more about how Rainier would hit Tacoma, specifically, The News Tribune asked some experts.
Here’s what you should know.
How would a Rainier eruption affect Tacoma?
The U.S. Geological Survey (USGS) states that Rainier hasn’t had a “significant eruption in the past 500 years.”
The city of Tacoma works closely with its USGS partners, said Tacoma’s Chief Emergency Management officer Tieka Adeogun. Any signs of impending eruption would spur officials into action.
“For right now, they (USGS) have not said that anything is going to happen with Mount Rainier,” Adeogun said. “So I want people to breathe — but understand that the hazard is real and the threat is real — and it could be 2,500 years from now; it could be 25 years from now.”
USGS notes in a 1998 Rainier fact sheet that eruptions produce lahars: quick-moving mixtures of water, mud and volcanic rock that behave and look like “flowing concrete.” While this type of slurry is dangerous, Adeogun said Tacoma would not be at a major risk for lahar activity. Most of the city is uphill.
A lahar would likely extend into Tacoma’s Tide Flats but take at least a couple hours to get there, she said. People would be evacuated out of that area, and roads would be closed in the event of an eruption. Lahar sirens are tested each month.
As for the cost?
“So when we talk with our port partners, we’re looking at millions of dollars in damage, right?” she said. “Especially if we get a pretty fast-flowing lahar, something that’s going to have a huge impact. Maybe it knocks over some cranes into the waters.”
‘Most dangerous volcano in the Cascades’
The lowlands around the Puyallup River, down to Commencement Bay, could be affected by a lahar, said Steve Malone, a retired seismologist with the Pacific Northwest Seismic Network. The farther away from the mountain, the lower and slower a lahar would charge.
Apart from the risk to life and limb, infrastructure would be jeopardized.
Similar to what happened with Mount St. Helens’ eruption in 1980, Rainier would show hints for days or weeks in advance, Malone said. Signs such as precursory earthquakes or steaming would grant extra time for authorities to plan and conduct evacuations if needed.
Mount St. Helens killed more than 50 people, but Malone said the death toll could have been far higher without the advance warnings.
Regardless, Rainier imperils the areas that surround it.
“It’s a heap of sort of unstable rock covered with lots of ice and snow,” Malone said. “So in that respect, I consider it the most dangerous volcano in the Cascades: its size, amount of ice and snow, and the fact that there are population centers directly in the path of potential lahars.”
How would a Rainier eruption affect Pierce County?
Other parts of Pierce County are at much higher risk of destruction compared with Tacoma.
Orting, for instance, has been described as “ground zero” for volcanic activity. One commenter on Reddit wrote in response to the CNN article: “Lahars are why you couldn’t pay me to live in Orting. Beautiful town, absolute deathtrap in that situation.”
The reason why USGS has focused so heavily on keeping an eye on Rainier is because of its proximity to population centers, noted Amy Gillespie, deputy director of Pierce County Emergency Management. The volcano brings two major concerns: ash fall and mudflows.
“When we look from a mudflow or a lahar perspective, really, we’re looking at the Ashford-Elbe area,” Gillespie said. “We’re looking at Orting, everything along the Puyallup River Basin and then the White River.”
In March, more than 45,000 students from Orting, Puyallup, Carbonado, Sumner-Bonney Lake and White River took part in the world’s biggest-ever lahar-evacuation drill, according to USGS.
A Rainier eruption also would be costly as far as emergency-response and debris-removal costs, plus temporary housing, she said.
Will there always be warning of a lahar?
The mountain is essentially monitored at all times, Malone said. It’s very unlikely that a volcanic event would sneak up without warning.
However, a no-notice or spontaneous lahar could occur in circumstances such as slope failure and intense rainfall.
“Phew. Then, a worst-case scenario is: It’s the middle of the night, and the weather’s awful, and here comes a lahar,” Malone said. “You’ve got to jump out of bed and try to get away.
“That’s a scary, scary scenario.”
Associated risks of Rainier eruption
Lahars aren’t the only thing we should be worried about if Rainier erupts. Air quality would plummet, Adeogun said — a hazard that sometimes gets overlooked.
Mount St. Helens’ last eruption caused ash to drop from the sky over a period of weeks, according to the U.S. Department of Agriculture. Rainier could disrupt the air quality in states as far away as Idaho, Oregon and California, Adeogun said.
Breathing in ash or volcanic gases can be detrimental to your health, according to the Centers for Disease Control and Prevention.
“A lot of the focus is largely on the lahars,” Adeogun said, “but when we look at the impact for Tacoma, that’s very minimal compared to the air quality that we’ll face in the city.”
How to prepare for when Rainier erupts
Adeogun recommends that households stock up on N-95 masks in preparation for a Rainier eruption.
Residents would need to close their windows and doors and shut off ventilation systems that connect to outside, she said. Avoid travel. It’s unclear how long a sheltering-in-place would last, but it could be a week “to well over a month.”
People should have nonperishable food on hand, she said. Stock up on water, too — a gallon per day per person, including pets. Adeogun said she’ll empty out old milk jugs and fill those with water.
In addition, it’s important to know where one’s community supports are located, such as food banks.
Adeogun said the city partners well with USGS and other jurisdictions in the county that are closer to Rainier.
“Just know that if we see something and we hear something, we’re going to start moving and making sure our citizens are as ready and prepared as possible,” Adeogun said.
Gillespie highlighted a county-wide Mount Rainier response plan that covers various cities and unincorporated areas— as well as neighboring jurisdictions, she said, citing Rainier’s potential statewide impacts.
The county has been enhancing the plan since 2020-21, Gillespie said. It focuses on notifying the public and first responders, evacuation routes, shelter guidelines and more.
Gillespie recommends signing up for Pierce County ALERT, which informs residents of emergencies. She also suggests having a battery-operated weather radio to receive Rainier notifications, something especially handy in the middle of the night.
Mike Halliday, spokesperson for the Pierce County Department of Emergency Management, said it’s important to build an emergency kit.
“We also really encourage people to get to know their neighbors,” he said. “Watch out for folks who you know need extra help during any sort of emergency — not just this.”
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