New tires have to be driven a few hundred miles on dry roads to rid the tread of parting agents and antioxidants applied during production. Not until the tread has been slightly roughened will the tire be able to make its true gripping power felt.

What's more, flooring it and slamming on the brakes can cause tire/rim slip in the first few hundred miles of tire use. That's because the lubricant used in mounting the tire has an initial tendency to reduce the adherence of these two parts.

You are thus well advised to exercise care with new tires. And keep in mind that winter tires fresh out of the factory will need a bit of time to attain full winter suitability.