What to do about Mount St. Helens and Mount Adams?

Dozens of local, tribal, state and federal officials gathered virtually and in-person on Feb. 19 to talk about how they’d respond if either Mount Adams or Mount St. Helens erupted. It comes in the wake of Mount Adams showing an increased amount of seismic activity.

The goal is to create a new Mount Adams/Mount St. Helens Coordination Plan, last updated in 2014.

“When we talk about volcanic eruptions, one of the biggest things we have to deal with is uncertainty,” said Volcano Program Manager Brian Terbush at the Cascades Volcano Observatory in Vancouver. “We don’t really know when it’s going to erupt, what direction, how much ash is going to be, whether it will be days, weeks, months of unrest. So, the best thing we can do on a coordination plan is who has what responsibilities, who shares information, when and at what level, who reports to who.”

“The most important thing is building connections with each other,” said Holly Weiss-Racine, a geologist and outreach coordinator with the USGS Cascades Volcano Observatory. “After Mount Adams woke up a little bit, it allowed us to rebuild our communication, so the mountain really brought us together again. … Having a volcano working group is a way to keep building our communication before we have an event to respond to.”

Typically, Mount Adams only sees one earthquake every two to three years. But from September of 2024 to January of 2025, there were roughly 12 small earthquakes. The largest earthquake was a 2.0. There hasn’t been activity on or near the volcano now for about two months.

Jon Major, the Scientist-in-Charge of the Cascades Volcano Observatory.

With only one permanent monitoring station near the volcano, the activity spurred USGS to set up temporary stations, some of which have since been removed or are now covered with snow. But there are five permanent monitoring stations that are on the way with permitting already done for four of them, according to Jon Major, the Scientist-in-Charge of the Cascades Volcano Observatory. Major said the goal is for the stations to start being installed this summer.

Scientists at the Cascades Volcano Observatory say that Mount Adams is generally not a highly explosive volcano. Instead, geologic evidence shows it would produce lava flows and ashfall – although there is a threat of a lahar and debris flows that have happened. About 6,000 years ago, there was a lahar that reached Trout Lake and beyond. And, about 300 years ago, there was another fairly large landslide-generated lahar that made it down to Trout Lake.

Mount St. Helens, meantime, is the most active volcano in the Cascades — and with the most kinds of monitoring equipment than any of the state’s other four active volcanoes. It’s remembered for its giant eruption in 1980 as well as smaller activity rebuilding its dome for four years starting in 2004. In May, the region will remember the 45th anniversary of the 1980 eruption and those who died or were impacted.

Wes Thelen, a geologist for USGS.

“This is the volcano we expect activity to happen next and this is the one we want to be ready for,” Wes Thelen, a geologist for USGS, told the coordination plan workgroup.

The current coordination plan is set up to help describe roles and responsibilities some agencies will be taking based on changes in volcanic alert level. The plan also outlines actions for preparedness, response and recovery.

“Coordination is more of a list of roles and responsibilities, while your standard operating procedures are what you do in different situations,” Terbush said. “So, having all of these people in the room, all of these people online, this is a good start.”

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