If people acted sensibly and stopped panic buying and filling the freezer with milk and bread and made sure they had enough fuel to get them where they need to be there wouldn't be shortages.Why do you need a full tank when your car will be stuck on the drive anyway?
I went into Iceland at lunch time and people were buying milk and bread by the trolley load,I heard one chap say to the till operator he would be back for more tomorrow as he couldn't carry any more
Years ago when there were no supermarkets and snow fell like this,everyone managed but while you have the news programmes showing people making sure neighbours have bread and milk and saying stock up and also telling you to make sure your tank is full of petrol in case you go out and get stuck then I am afraid empty shelves and pumps will be the norm..