Looking for a durable, waterproof and warm boot for my daughter attending Univ. of Michigan this winter. Needs to handle ice, snow, slush and -degree temps. They don't close school for snow. We were getting ready to purchase the Sorel Caribou, but reviews have been bad for "cracking" since Columbia took over that brand. She likes that style....so she was also looking at the Merrell Tremblant Mid Polar boot.  Do you have any recommendations for us?