Besides ensuring that the tread on your tyres are at the legal limit of 1.6mm, you may want to invest in tyres that are specially made for snowy, icy or wet conditions.
Winter tyres provide extra grip and stability for your vehicle in unusual conditions. Remember it takes longer to brake in bad conditions and having extra grip and stability on your vehicle, when you need it, could mean saving your life and those of your passengers and other road users.