The proper ski gear will keep you warm. Invest in a ski mask, water resistant clothing and boots.
This is good for snow tubing, sking or snow boarding.
There are lots of shops that offer ski wear if you have forgotten something or need anything.
Toiletries and Medical Supplies: Bandaids and Tylendol for muscle aches & sprains
Photo Equipment: Keep your camera zipped up in your pocket.
Clothing/Shoes/Weather Gear: If you are coming to ski, I would suggest wearing ski suits or whatever, but beware, most people are a little weird and wear mostly jeans and flannel shirts.