First, be prepared to a slower working condition, everything slows down when it gets cold.
Film gets very brittle and razor sharp. Load magazines in warm condition if possible. If possible, 35mm cameras need to be loaded in warm conditions; otherwise a lot of patience is needed if they are loaded in cold conditions. The 16mm camera with coax magazines are easier to use.
If equipment is moved from a warm area into the cold, and it is not snowing you have no problem. If it is snowing, either pre chill the camera before going into the snow storm, or protect the warm camera with a wet suit or plastic covers. If you do not follow the precautions, the snow will hit the warm camera, melt, seep into the camera, and will freeze once the camera gear gets cold and the camera will stop working.
If equipment is moved from the cold into the warm environment, seal the individual components air tight in plastic bags in the cold. Place a towel under the gear in the camera before moving into the warm condition. Once inside a warm room, condensation will form on the inside of the plastic bag and will run down inside the bag, and the condensation is collected by the towel. Do not open the sealed bag prematurely, or condensation will form inside the camera gear including the lenses.
It only takes few degrees temperature difference to create condensation.
Once condensation forms on the inside of lenses, the damage is done and leaves many times spots on the inside of the lens elements.
Have the gear cold weather prepared and tested by the rental facility you rent from, it is recommended that mechanical parts on camera and lens gear is lubricated with special cold weather lubricants.
Have the cameras tested in a freezing chamber, not for the mechanical but for the electronic components in today's sophisticated, electronic camera gear. Bring along spare electronic boards.
Have enough battery power. Remember the Ni Cad batteries lose 10% of their rated capacity for every 10 degrees below 40 degrees Fahrenheit. It is easy to figure out what is left in good batteries at minus 20 degrees. Keep batteries warm, possibly under your coats etc.
Power cables may crack, and zoom motors work slower.
Any more questions call the manufacturers for more information.