Most climbers encounter the onset of mild hypothermia at one point or another during their careers. Many of us have certainly hung at a belay station, shivering, and wondering why we didn't bring that extra jacket. But for most of us, things never get any worse than that.

The Mayo Clinic has an excellent description online of hypothermia and its treatment. As most of us will never encounter hypothermia in a context where a patient could be warmed in a hospital, some of the information on the site does not pertain to us. However the following description of what to look for is incredibly pertinent to the backcountry traveler.

Hypothermia usually occurs gradually. Often, people aren't aware that they need help, much less medical attention.

Common signs to look for are shivering, which is your body's attempt to generate heat through muscle activity, and the "-umbles":

* Stumbles
* Mumbles
* Fumbles
* Grumbles

These behaviors may be a result of changes in consciousness and motor coordination caused by hypothermia. Other hypothermia symptoms may include:

* Slurred speech
* Abnormally slow rate of breathing
* Cold, pale skin
* Fatigue, lethargy or apathy

The severity of hypothermia can vary, depending on how low your core body temperature goes. Severe hypothermia eventually leads to cardiac and respiratory failure, then death.

Severe hypothermia in the field requires immediate attention. Wilderness medicine providers have devised a simple treatment which relies on a variety of materials that most backcountry travelers normally carry. They use these pieces of equipment to create a "themal burrito" or a "hypo-wrap."

Thermal Burrito or Hypo-Wrap

1. Lay out a tarp on the ground.
2. Place 1 or 2 pads down on top of the tarp. Two pads are always better than one.
3. Stack three sleeping bags on top of the pads.
4. Place the victim inside the sleeping bag in the middle.
5. Wrap the victim in the tarp.
6. Provide the victim with hot water bottles. These should be placed under the arms and at the crotch. Additional bottles may be held or placed at the victim's feet.

A Themal Burrito
From the Wilderness Medicine Institute 
This technique is featured in WMI Wilderness First Responder Courses.

Hypothermia is a dangerous and often hidden predator in the backcountry. There is no question that the best way to deal with it is to completely avoid it. The best way to completely avoid it is to pay attention to yourself as well as to those around you. Wear appropriate clothing for your environment and try to keep things dry.

--Jason D. Martin