Not necessarily. After Katrina, even
Walmart was closed for days. Our entire city was without power. They finally started letting a few people into Sams and Walmart at a time but there was no power. It was a couple of weeks before the stores could restock. Trucks were trying to deliver ice to people not restock grocery stores. Again, have you been in one of these storms? Comparing it to an ice storm is comparing apples and winter coats. Not even in the same ball park.
When trees are down, power lines and power poles are down--vehicles cannot get on the road. Trucks cannot deliver. When the power is off for miles around, stores have a hard time operating if they are able to at all. They can't sell gas without power.