Volcano in the U.S. Could Erupt Any Moment and Kill Tens of Thousands

Experts warn that it’s only a matter of time before Mount Rainier, one of the most dangerous volcanoes in the U.S., unleashes its fury on the Pacific Northwest. This massive, active stratovolcano towers over nearly 90,000 residents in cities like Seattle, Tacoma, and Yakima in Washington, as well as Portland, Oregon.

While Mount Rainier hasn’t erupted in over a thousand years, scientists remain vigilant due to its unpredictable nature and the massive destruction it could cause if it blows. “Mount Rainier keeps me up at night because it poses such a great threat to the surrounding communities,” volcanologist Jess Phoenix, a spokesperson for the Union of Concerned Scientists, told CNN.

When Mount Rainier eventually erupts, it won’t be lava flows or choking clouds of ash that pose the biggest threat—it’ll be lahars: powerful, fast-moving mudflows that can devastate entire communities in minutes. According to the U.S. Geological Survey (USGS), large lahars can destroy, bury, and carry away almost anything in their path.

“Tacoma and South Seattle are built on ancient mudflows from previous eruptions of Mount Rainier, some as thick as 100 feet,” Phoenix noted. This tells us that these heavily populated areas lie right in the path of potential lahars from a future eruption.

While Mount Rainier looms over Olympia, Washington, with over 50,000 residents, its reach extends even further, threatening nearby cities and communities.

Lahars are typically caused by volcanic eruptions that rapidly melt snow and ice on the volcano’s slopes, triggering landslides of mud, rock, and debris that race downhill. But eruptions aren’t the only way lahars can form. According to the Seismological Society of America, these destructive mudflows can also be triggered by weakened slopes from past eruptions or heavy rainfall after an eruption.

The deadliest lahar in recent history occurred in 1985 following an eruption of Colombia’s Nevado del Ruiz volcano. Within hours, mud, snow, and rock engulfed the town of Armero, killing around 25,000 people. This disaster, known as the Armero tragedy, remains the costliest volcanic disaster in history, with an estimated $1 billion in damages.

A similar event occurred in 1980 when Mount St. Helens, just 50 miles from Mount Rainier, erupted, sending lahars that destroyed over 200 homes, 185 miles of roads, and contributed to a death toll of 57. These tragedies have given scientists critical insights into the dangers lahars pose to communities near active volcanoes—and they’re using that knowledge to prepare for the worst-case scenario at Mount Rainier.

In addition to the tragedies, images from the Semeru eruption in Indonesia in 2022 show villages submerged by lahars, highlighting the widespread devastation they can cause.

Over the past two decades, scientists have made significant improvements to lahar monitoring systems around Mount Rainier. The Mount Rainier Lahar Detection System, which includes seismometers and other instruments placed along the volcano’s slopes and key lahar pathways, can now monitor in real-time. When this system was first created in 1998, it was hampered by outdated technology, leading to delays in detection. But with the new technology, authorities can act faster when a lahar is triggered.

Cities near Mount Rainier have also been preparing for the possibility of a future eruption by honing emergency response strategies. On March 21, 2024, more than 45,000 students from communities south of Seattle and west of the volcano will participate in the world’s largest lahar evacuation drill, according to the USGS.

With these efforts in place, the Pacific Northwest is gearing up for the inevitable eruption, which experts believe could happen at any time.