One interesting thing is that North Bend is alongside a highway/railway/river. Even if there were multiple independent cables running alongside the river, I suppose a large landslide could knock them all out. There are railway tracks on both sides of the river though, and phone lines were often run alongside railway tracks (or roads), so even though it's one valley, two fiber paths should be possible.

Ideally you'd ensure geographically diverse routes for internet fiber, but I don't know how easy that is for legacy telephony networks.

https://www.google.com/maps/place/North+Bend,+BC,+Canada/@49...