[Rockhounds] Why Mount Rainier is the US volcano keeping scientists up at night

[Kreigh Tomaszewski]

The snowcapped peak of Mount Rainier, which towers 4.3 kilometers (2.7
miles) above sea level in Washington state, has not produced a significant
volcanic eruption in the past 1,000 years. Yet, more than Hawaii’s bubbling
lava fields
<https://www.cnn.com/videos/us/2022/12/04/hawaii-mauna-loa-volcano-eruption-culture-pele-ilihia-gionson-intv-whitfield-nrtf.cnn>
or
Yellowstone’s sprawling supervolcano, it’s Mount Rainier
<https://cnn.com/2024/06/12/us/mount-rainier-missing-skier-death/index.html>
that
has many US volcanologists worried.

“Mount Rainier keeps me up at night because it poses such a great threat to
the surrounding communities. Tacoma and South Seattle are built on
100-foot-thick (30.5-meter) ancient mudflows from eruptions of Mount
Rainier,” Jess Phoenix, a volcanologist and ambassador for the Union of
Concerned Scientists, said on an episode of “Violent Earth With Liv
Schreiber,” a CNN Original Series.

The sleeping giant’s destructive potential lies not with fiery flows of
lava, which, in the event of an eruption, would be unlikely to extend more
than a few miles beyond the boundary of Mount Rainier National Park in the
Pacific Northwest. And the majority of volcanic ash would likely dissipate
downwind to the east away from population centers, according to the US
Geological Survey <https://pubs.usgs.gov/fs/1997/0065/pdf/report.pdf>.

Instead, many scientists fear the prospect of a lahar — a swiftly moving
slurry of water and volcanic rock originating from ice or snow rapidly
melted by an eruption that picks up debris as it flows through valleys and
drainage channels.

https://www.cnn.com/2024/06/23/science/mount-rainier-volcanic-eruption-lahar-scn/index.html