What are your main concerns?

[Devonian]

For me, food is the big unknown.

I feel that Security, Shelter, Water can all be managed without too much concern.

Disease is a total unknown, but not something I'm overly concerned about.

The problem with food is that whatever supplies you have they will not last indefinitely and also if you have been driven from your home, you could well loose all your supplies including food being grown in the garden/greenhouses etc. So no matter how well you prep, you could easily be left short.

Also depending on the event there could be a 'Significant' amount of competition out there foraging; hunting; stealing; collecting whatever processed, natural, wild foods etc that are available.