I drove my 215 21" summer tires in ice and snow two months ago (Sunrise, AZ @10,000ft elev) and had to drive carefully. I thought it was do-able as long as I drove nice and easy and allowed sufficient space to slow down. In short: it is not impossible to drive but it is not great either....

Best thing to do is to find an empty stretch and have a few emergency brakes to find out how much grip you have before you take it out.