As a part of the body becomes chilled blood flow is restricted in an attempt to save heat and prevent hypothermia, which lowers the temperature further causing more damage. Frostbite prevention is also the parent's responsibility. Once again making sure your child has the proper clothing is key. Exposed flesh equals frostbite on a cold windy day, so gloves, a hat, and in more extreme environments scarves, ski masks, and even ski goggles to protect the eyes may be needed. Children should be briefed on the symptoms of frostbite, and group leaders should also know how to identify and treat it.
Dehydration is probably the most senseless of injuries that can happen to a child.
Proper hydration out in the field is the responsibility of the leaders. When your child goes out for an adventure make sure they will have an adequate water supply. Buying a couple bottles of Avian at the convenience store may save you some time, but it is doing your child a great disservice. Take the time and spend a few dollars on some proper water bottles. If it is a struggle to get your child to drink water invest in some powered sports drink mix.