“Snow has two simple ingredients: cold and moisture. Warmer air collects moisture like a sponge until it hits a patch of cold air. When temperatures dip below freezing, a lot of moisture creates a lot of snow.”
Elaborating on his comments – warm, moist -30C air sweeps down from the Arctic and hits the much colder 0C air in Texas. This causes record snow to fall in locations that used to be warm before global warming made them cold.