It will take a few days for awareness to sink in, yes. People will certainly sit around at first going "Oh, it's an event, or just a few days of bad weather."

You haven't seen this type of plotting before because we haven't had an event happen like this before. I believe as it gets longer, it will only make characters more concerned.

I'm not sure why only one or two would be actively thinking about survival in this city. It's snowing nonstop and cold, and everyone eats. Even when it's just a couple-day event, characers react quickly. They don't know what's going to happen.

Yes. We took more than a passing glance at the calendar. The details of this have been in consideration since September.

It is hard. But it is survivable.

Editing to add: I'd forgotten the drought and sandstorm. We've had big weather plot before back in summer. Characters responded, drew together, worked. They all survived.