I live about 60 miles from the mountain. I’ve done lots of research into what could happen. If Rainier should erupt, the lahars would indeed destroy a lot of communities around the area. If we get as big a lahar as the Osceola Mudflow back a few thousand years ago, it could reach all the way to Seattle by way of the Duwamish River valley. The major city more likely to be affected by a Rainier eruption would be Tacoma. It’s very likely that the port of Tacoma would be pretty much destroyed.
The towns that could be wiped out or at least severely damaged would be small places, like Orting, Sumner, Enumclaw, and a good chunk of downtown Puyallup. Lahars could also go up as far as Kent and Auburn. But Seattle or Portland being destroyed? Not much of a chance of that.
Another thing to consider is ashfall. Back in 1980, I lived in Spokane which was 250 miles away from Mount Saint helens. Even there, we got a couple of inches of ash. If Rainier were to go, I almost expect that places closer to Rainier could see ashfall measured in feet.
No doubt, if Rainier erupted, the devastation would be catastrophic, I’m pretty sure that hundreds if not thousands of people would end up being killed. But, major cities like Seattle and Portland wouldn’t be damaged as badly as some people think. Rainier’s big, but not that big.
we got a couple of inches of ash. If Rainier were to go, I almost expect that places closer to Rainier could see ashfall measured in feet ... Rainier’s big, but not that big.
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Note: volcanic ash is just incinerated rock; feet of it will collapse roofs, buildings, freeway overpasses etc.
Mount Rainier ranks as the tallest volcano in the Cascade Range and the highest peak in the U.S. state of Washington, with an elevation of 14,409 feet (4,392 meters)
I lived in Kennewick when it blew. We could ser the ash cloud heading NE and all we got was a very light dusting similar to our typically dust storms we would get in those days.
good luck to you and God bless.