I have only heard of Indian oral traditions of the far older explosive blowout of the Crater Lake Caldera. Also of rock slides damning the Columbia River upstream of Portland Oregon.
Tales of the Jan 30 1700 offshore earthquake and its tsunami destruction up and down the BC-WA-OR coast could only be carried by (be created by?) surviors of tribes who were back from the coast and inland, uphills that particular night. But, even with no coastal tribe surviors, in the 104 years between the tsunami and the arrival of Lewis and Clark to the coast, it would seem near-certain that people would return to the rivers and bays from inland. Or remember tribes that used to be on the coast.
I do not recall their reports mentioning past tribes, but rather pointing that there were no tribes nor fishing villages. And, obviously, no ports or European colonies either.