I feel like this is equally evidence for incredible preparedness and flexibility though? The fact that such a major event was only scary for a week seems like a good thing? Even in a perfect world, there will be extreme weather events, and if people can't survive a week in their homes without outside help, that seems like the problem rather than evidence that we can't adapt to disaster. I assume your parents will be sure to stock up on certain essentials going forward.
It was scary for a week because they were down to a single remaining point of failure (Abbotsford pumping station). If that station failed (which was quite possible, due to rising floodwaters), the Fraser river would have flooded the valley, and Highway 1 would have been... Gone. Not 'flooded for a week', but 'flooded permanently'.
On the other side of the city, mudslides destroyed bridges on the Coquihalla highway - which will take at least 2 months to be made passable - and things won't be back to normal for another year.
Had the pumping station failed, and the highway flooded, it's entirely unclear what anyone could have done in that situation to keep Chilliwack supplied over the next two months.
Certainly folks could be evacuated or supplied with essentials if it came to that. They did so as far away as Afghanistan.
It would require some adjustment and dealing with adversity, but your comment makes it sound like everyone would starve to death and be found having eaten each other or something if the roads were out for a week.
There was no danger to Vancouver. It's a port city, that could always be supplied by I-5. There was a lot of danger to Chilliwack, if Highway 1 could not be saved (Which, thankfully, did not turn out to be the case).
My parents live in Chilliwack. It was a really scary week for them, between their need for prescription medication and animal feed.