Surely you are not claiming British Airways to be a God-like creation?

Seriously, snowstorms in the New York winter really wouldn't enter into the even the widest definition of act of God/force majeure. New York winters form part of the environment BA operates in and the airline could reasonably be expected to have contingency plans to deal with delays caused by snowstorms.

So BA accepts the risk of service disruption, and builds the risk into its operations and into its business plan. In the event that passengers cannot be carried, then the EU Regulation aims to ensure the airline shoulders the financial consequence of taking on the risk, rather than pass these on to the passenger.