What happens to the supply of food when there is a disaster or a calamity?

What happens to the supply of food when there is a disaster or a calamity?
Or
A natural calamity like drought may affect the infrastructure but definitely will leave its toll on ‘food security’. Justify by a suitable example.

Production of food grains decreases due to the calamity or the food grains are not able to reach the poorest people, i.e. accessibility is affected. The shortage of food results in a price increase. If it affects large areas, it can result in deaths due to starvation or even a famine. An example is the Bengal famine of 1943, in which More than 3 million people died.