In Oregon, after some severe forest fires, ice storms that shut down whole towns, and the possibility of a Cascadia Subduction Zone event (ie, ~9.0 earthquake) They recommend keeping supplies for 2 weeks to allow time for local areas to get regular supplies of food, water, etc. https://www.oregon.gov/oem/hazardsprep/pages/2-weeks-ready.a...
Homes being prepared also dramatically reduces the need for distributed aid to these people. That could mean that labour to restore minimal infrastructure is more available. Feeding people in situations like that takes immense effort.
For a world affecting CME, it might take a month but a 9.0 magnitude earthquake is not going to destroy the entire world, so you don't need a years worth of food before help arrives. we're talking about a little extra bit of water and food, not an underground bunker. Help from outside the affected area will be coming.
