We keep our MRE's in the basement. Mostly because we will shelter in place when possible.

Our car rations do not need to be long-term so we keep 3600Kcal Mayday "food bars". They taste ok - I always check how thigs work before adding them to our supplies. They will keep you alive for a couple of days. These are made so that they are impervious to changes in temperature. (as far as nutritional value)

H2O is a different matter. It DOES freeze in your trunk.