Holyscroller was a Freeper, and she wrote 4 books on Mt Rainier. (She passed in 2020). Whereas they say Mt Rainier had no “lava flows” they are correct, but Mt Rainier has had a lot of pyroclastic flows, which could be more dangerous than lava. A pyroclastic flow is when superheated steam interacts with dirt to create boiling mud. Evidence suggests that multiple times Rainier has sent this boiling mud down, with walls of it up to 60 feet deep, traveling at 60 mph, and making it as far as Puget Sound at Tacoma. Pyroclastic mud is more dangerous than lava, because it reaches speeds that lava cannot even begin to approach, and flows much further than lava can (evidence of up to 60 miles).
I knew what a pyroclastic flow was (the Indian paint pot in Yellowstone being of such a material), but was unaware of the particulars re Mt. Rainier. Thank you!
Also a threat from a Mt. Rainier eruption are lahars (massive mudslides). These will be triggered upon eruption by the melting of the massive snow pack on Rainier that instantaneously becomes billions of gallons of water that will destabilize mountainsides and mix with dirt creating huge mudslides traveling at the speed of freight trains. Communities at the foot of the mountain could be hit within an hour of the eruption by lahars that scour the ground and leave nothing in their wake. Historically, some of these lahars from Mt. Rainier eruptions have reached the Puget Sound.
A worst case scenario of a major eruption of Mt. Rainier could make the 1980 eruption of Mt. St. Helens look like a grade school science project in comparison.