Who will stop the Rain-ier?

Scientists are warning that Washington’s Mount Rainier could unleash a catastrophic mudslide that has the potential to devastate three large towns within minutes.

Often considered the crown jewel of Washington postcards, the over 14,000-foot-tall mountain is deemed the most dangerous in the US due to its towering height, frequent earthquakes, and precarious location upstream of a population center with over 100,000 people.

While there is no evidence Rainier is about to blow its stack, magma is not the most dangerous fallout from the Cascade range’s preeminent volcano.

Far more devastating are lahars, violent slurries of rocky debris, mud and meltwater that originate on the mountain’s slopes and flows downhill at over 100mph, devastating anything in their path in just minutes, Popular Mechanics reports.

They can also measure hundreds of feet tall and travel over fifty miles away from their origin point.

“They are complex phenomena that change a lot during transport,” National Autonomous University of Mexico volcanologist Lizeth Caballero García, told Popular Mechanics. “They can grow, they can dilute.”

Mount Rainier’s 25 major glaciers harbor more than five times as much snow and ice as all the other Cascade volcanoes combined, meaning that just a minor thaw could trigger a lahar of apocalyptic proportions without warning.

This would be devastating given that the volcano’s forecast lahar path traverses Washington’s Pierce County, a hub of 150,000 people that’s located just around 60 miles from Seattle.

Were one of these mudflows to burst forth from Rainier, it would run roughshod over the towns of Orting, Puyallup, and Sumner in just 30 minutes, potentially impacting 60,000 residents.

Worst of all, these deathslides don’t require an eruption to wreak havoc — a “no-notice” lahar can be triggered by heavy rainfall, snow melt or even a dam failure.

“[No-notice lahars are] the thing that goes bump in the night,” said former Cascades Volcano Observatory (CVO) geophysicist Andy Lockhart. “It creeps me out.”

One of the deadliest Lahars occurred in November 1985 when Colombia’s Nevado del Ruiz volcano blew its top, causing a torrent of mud, rocks, lava and icy water to inundate the town of Armero, killing over 23,000 people in just minutes, CNN reported.

To avert a similar calamity, the CVO has installed a network of monitors throughout the cascade range to pick up lahars and seismic activity and transmit the info back to disaster responders so they can act fast.

Meanwhile, two years ago, over 45,000 students and staff from over 20 schools in communities west of Rainier participated in one of the world’s largest lahar drills.

As in years past, the simulation proved that fleeing on foot is the most effective way to get out of harm’s way in the short timespan that lahars allow.