Lahars triggered by an eruption of the Nevado del Ruiz volcano buried an entire community in Armero, Colombia, on Nov. 13, 1985. More than 20,000 lives were lost.
Scientists and officials say it was a tragic teaching moment for valley communities around the world, including Orting, the East Pierce city of more than 6,700 in the shadow of Mount Rainier.
“That’s a lot of people and a lot of lessons learned,” Orting fire chief Zane Gibson said of the 1985 tragedy.
Gibson was one of 10 local and state officials — about half from Pierce County — who traveled to Colombia last August to learn more about lahars and disaster response.
Now they’re reflecting on their relationship with the Nevado del Ruiz area, sharing it with the public and looking to expand on it.
They’re also building awareness of lahar risks back home. This month, the U.S. Geological Survey will install new signs along the Foothills Trail in the Puyallup Valley.
The group spent a week traveling to five cities in Colombia, working 14-hour days that Gibson said weren’t long enough to learn everything about lahars — destructive mudflows made up of water, rocky debris and pyroclastic material from volcanic eruptions.
One striking detail about Armero stood out for Gibson: “This could be Orting,” he said.
As Colombians dealt with the aftermath in Armero and surrounding areas in 1985, scientists with the USGS traveled to the region to assist crews and learn about lahar emergency response.
Today, federal funding has helped expand that outreach to local officials who are threatened with a similar disaster that has yet to occur.
Gibson said the August trip was followed by a visit from the Colombians in September to learn about preparedness around Mount Rainier.
“It’s an exchange of information,” he said.
Carolyn Driedger, a hydrologist and outreach coordinator for USGS who also traveled abroad with the group, said the exchange gives local officials the rare opportunity to learn from the experiences of others before a disaster happens at Mount Rainier or other peaks in the Cascades.
Driedger said local residents, who have long heard about the threat of lahars, face hazards similar to those in Armero.
She said Mount Rainier and Nevado del Ruiz are both large, ice-clad volcanoes. Orting and Armero are located similar distances from their mountains, she said, and both communities are connected to the base of the peaks by narrow valleys.
Those channels and steep slopes create an intense snowball effect that causes a lahar to quickly accelerate down the mountain, she said.
Native oral tradition talks about Mount Rainier “losing its head” and coming into the valley, Driedger added, and similar folklore exists in and around Armero.
Emergency responders in both communities also serve similar populations of about 13,000 people.
The parallels helped paint a picture for Orting and other officials, showing them how the real thing might unfold.
Gibson said the most powerful part of the trip was talking to survivors who lost family members in the 1985 lahars. Driedger agreed.
“Stories are really powerful,” she said. “It’s one thing to read something in a textbook, it’s another thing to be there and talk to survivors.”
Gibson said what he learned abroad will help his department better prepare for a lahar. He said Orting Valley Fire & Rescue is working on a more detailed evacuation and response plan.
Other representatives around Pierce County, including fire chiefs and school administrators, are being considered for future trips to Colombia.
Driedger, who’s based in Vancouver, Washington, said the overall goal is to inform people about the threat of lahars, not scare them.
“We certainly don’t want people to be frightened,” she said. “We want people to be aware of the hazards in the valley.”
Driedger said the new USGS signs directed at residents living on the Puyallup Valley floor will share information about evacuation, lahar hazard zones and more.
Traditional lahar preparations will continue as usual, including Orting’s biannual school evacuation drills and regular tests of 31 sirens in at-risk communities.
Gibson said a reawakened Rainier and a disastrous lahar may not happen during this generation or even the next, but it’s important that residents remain alert.
“It’s a high-risk, low-probability event,” he said. “But we owe it to our community to be prepared.”