How does the quattro system in the Audi A3 improve traction in snowy conditions?

I've heard that the quattro system in the Audi A3 is great for driving in the snow, but I'm not sure exactly how it works. Can someone explain the technology behind it?

The Audi A3's quattro system uses a center differential and electronic traction control to distribute power to all four wheels, allowing for better traction in snowy or slippery conditions. My personal advice for driving in the snow is to accelerate and brake gently, and to avoid sudden movements.