What does Islam say on purchasing and storing food as a precaution during any disaster? At what point does it constitute hoarding and becomes forbidden?
as salam alaikum
storing food as precaution during disasters in itself is allowed and it could be also praiseworthy if the intention is to share it with others in times of hardship. However different situations call for different ways of dealing; for example it wouldn't be correct to store extra-food for ourselves while others cannot afford, or barely afford, basic necessities. In such case we should try to give priority to the needy, kids and elders in difficulty and offer our help to them if and when needed.
With prayers for your success.