When disaster strikes, we want to take care of the helpless: the very young and the very old. Babies of course need extra care, and pople wonder whether they should provide formula. Short answer: No. In devastated areas, drinking water is difficult to find, and often suspect. Far better to avoid exposing babies to extra germs whenever we can.
There are many gray areas in life, but raising healthy happy babies is not one of those areas. No matter how horrible a disaster, no matter how risky life may become, there is no substitute for old fashioned mama milk. Formula is damaging to baby brains, significantly lowering their expected IQ. It also lacks vital antibodies and enzymes, making them more suspect to disease.
No matter how much money companies like Nestle spend to spread falsehoods about the "benefits of formula," the cold hard fact is that cow milk supplemented with vitamins will never be as good for your baby as the food your mama-ry glands will provide.
It isn't pure instinct though, you'll need to talk to a lactation consultant and/or mamas with experience. And while breastfeeding is difficult in the first few days, it quickly becomes an integral part of your day, requiring none of the shopping, refrigerating, heating and mixing of those synthetic milk products.