Appendix T: Emergency Snow Shelters
TBSP Patrollers are expected to have the skill to create and use emergency survival shelters in the snow. These are three snow shelter techniques taught by the patrol.
Each patrol carries a megamid as part of the group modular patrol kits. These lightweight and highly versatile tents are easy to set up and the correct snow technique for constructing a megamid is taught as part of the mountain travel and rescue course. Megamids can also be used for sheltering patients and for general environmental comfort on snowy days. The downside to the megamid shelter is its lack of thermal insulation.
Emergency Snow Trench
The TBSP emergency snow trench is designed help trap heat in survival situations, and is a single-person snow shelter. A diagram of an emergency shelter can be found in the NSP Mountain Travel and Rescue text on page 36. The TBSP emergency shelter is designed to be a custom fit for your body. You are the stove, so one-size-fitsall doesnt apply. Study the diagram. Plug in the following measurements:
- Distance A = the length of your skis (or board) less 12 inches
- Distance B = the width of your shoulders plus 12 inches
- Distance C = your height plus 8-12 inches for wiggle room
To construct the shelter:
- Ski pack an area about 9 x 12 feet; boot pack the area if you have time
- Using your skis and poles as measuring guides, dig the shelter
- Using the short edge of your tarp as a guide, create the air vents with a ski pole: one vent opposite each grommet hole [WARNING: THIS SHELTER MUST HAVE AT LEAST ONE UNOBSTRUCTED AIR VENT]
- Run the 60-inch air-vent cords through the air vents
- Place your poles then skis over the shelter hole
- Using tent hitches, install 30-inch guy lines in all grommets of your tarp except those along the air-vent edge and the center grommet on the foot end of the tarp, then fasten a deadman to each guy line. You can attach a guy line and deadman to the center grommet at the foot end of the tarp, but it must be long enough to clear the excavated foot compartment of your shelter.
- Place your tarp over the poles and skis (the edge near the air vents is critical, and must be placed so the vents are not covered)
- Dig holes for the deadmen and place all deadmen
- Adjust the guy lines so the tarp is snug
- Fold back the tarp edge near the air vents and enter the shelter
- Attach the air-vent cords to the tarp
- Unfold the tarp to its full length and tension the air-vent cords from the inside
- To exit the shelter untension the air-vent cords, fold back the tarp and detach the air-vent cords from the tarp if they are in your way.
- Cut and pre-install guy lines on your tarp with tent hitches in all grommets except those along the air-vent edge [or see next tip].
- If you use clips on your guy lines you can put all of the cords in a ditty bag and simply attach them to the tarp when they are needed.
- Cut 1/2 inch by 2-3 inch dowels for deadmen. Drill a center hole in each dowel. Feed the cord through the hole in the dowel, then create a figure-eight stopper knot or attach a cord lock to hold the dowel in place. Cord locks make it easier to shorten the guy lines before placement.
- Make the 60-inch air-vent cords from a different color parachute cord. They should have a clip on one end and a 1/2 inch by 6-inch dowel (with a center hole) on the other, backed by a cord lock. To tension these air-vent cords push the dowel up the cord until it rests across the air-vent hole inside the shelter. Then follow with the cord lock to tension the cord and to hold the dowel in place. To exit the shelter, simply reverse this procedure.
- To feed the air-vent cords through the air vents clip or tie the upper end of the cord to the strap of the ski pole, then from inside the shelter stick the strap end of your pole up the vent until it pokes out above.
- For a warmer shelter, try spreading a layer of light snow over the tarp before you enter the shelter.
- Use your shovel handle to keep the air vents clear during your stay.
Other snow shelters
TBSP also instructs candidates in the construction of snow caves and other snow shelters. Tahoe Backcountry Ski Patrol Manual