They’re overinflating the risk of that happening by a wide margin.

The last tsunami didn’t even wipe out the town, in fact it didn’t kill a single person in Port Alberni despite destroying 55 houses and damaging hundreds of others. It’s unlikely a second one would be worse considering that the earthquake that caused that one is still the strongest earthquake ever recorded in North America.

Also, the last one also happened in 1964, long before things like earthquake and tsunami warning sirens were a thing.