At least in Oregon, I-5 is 50 miles away from the coast and separated from it by a small mountain range. I don't think we're too worried about tsunamis getting all the way to I-5. Definitely will get to Highway 101 in some spots, however. But a lot of the coastline is tall enough that you can usually find a safe place nearby if a tsunami warning sounds.
Yep. I only recall seeing them in Oregon though - not California or Washington (Washington has warning signs for everything else though - including no warning signs - https://i.imgur.com/T868pkg.jpg )
Washington has them, it was one of the first things I noticed when I got the motorcycle out for a coastal ride when I first moved here 20-some years ago. Couldn't tell you exactly where, but they're there and within an easy Saturday ride from Redmond. (Westport or Grayland, maybe?)
It's been a few years, but I don't recall them in Kalaloch, La Push, or Ozette... but then that was '09. The picture of the no warning signs warning was on the road to Ozette. It does appear that they are there now, so it might have been me misremembering ( https://goo.gl/maps/ofY3GGHDnuG5GWaZ6 )
> But a lot of the coastline is tall enough that you can usually find a safe place nearby if a tsunami warning sounds.
On the bright side, you won't need a siren, If the ground drops by 10 meters over the course of 5 minutes and you can't stand up because of the shaking, you can be sure a tsunamui up to 30 meters high will be there in an hour or two.
While some sections of I-5 are probably within the tsunami zone, I think much of it is beyond it. IIRC (I have not read the article since its original publication) this rule-of-thumb encompasses all the posited earthquake's structural and infrastructural damage at a level calling for FEMA-level assistance.
The remark is clearly only intended to give an impression of the magnitude of the worst-case scenario.
separately, there’s risk from lahars from mt. Baker and mt. Rainier. Catastrophic Baker lahars could potentially bury even Renton based on some estimates.
> The Sandy River was originally named the Quicksand River by Lewis and Clark in 1805 (Moulton and Dunlay, 1990). Expedition members noted that the river (a) was ~275 m wide at its mouth and for several kilometers upstream on the delta (30-150 m wide there today); (b) had a number of mid Channel Islands; and (c) had flow which was turbid and very shallow (resembling the Platte River in Nebraska, they noted). It was given its name because "the bed of this stream is formed entirely of quick sand."
> What happened? The answer lay 50 miles away at Mount Hood. An eruption in the 1790's caused a tremendous amount of volcanic rock and sand to enter the Sandy River drainage. That sediment was still being flushed downstream when Lewis and Clark saw and named the river. Since 1806, the river has removed the excess sediment from its channel.
