[Dean]

Here is one useful quote:

Originally Posted by CNN & Michelin Engineer(2002)

In contrast, winter tires are designed with softer rubber compounds that maintain their grip in freezing temperatures. More important, their deep treads are densely packed with small crosshatchings called sipes. Like the edge of a ski, the thousands of tiny sipes carve deeply into the snow to deliver traction. "The name of the game is how many biting edges you can get into the snow," says Ron Margadonna, technical marketing manager for Michelin North America.