Not many tools, really. A good snow shovel is probably the best thing to carry, something like Life-Link’s Himalayan Shovel ($60; www.life-link.com), a big shovel with an aluminum blade and D-shaped handle that will really move the powder. Another shovel that has an extremely ingenious design is the Snowclaw ($14; www.rei.com). It’s just a big plastic shovel blade with side cutouts for your hands. It offers extremely fast digging in soft snowyou can move four shovelfuls of snow in the time a person using a “conventional” shovel will move one. For fine-tuning a cave, ice axes work well, as do snow saws such as the Life-Link Snow Saw ($50). To cut down on the soaking your hands are apt to receive, pack a pair of heavy rubber gardening gloves that extend up your wrist and fit over wool or other insulated gloves.
As for the digging part, just make like a gopher and dig. It’s usually best to start near a big rock, short cliff, or maybe a bank of trees where the snow has drifted. You want to have a floor of snow, not dirtmuch more comfortable to sleep on. Plus, the slope of the snow in a drift will help create a natural dome. Start low, dig down a little, then work your way up. In powdery snow, a shovel will be sufficient. If the stuff is harder, use an ice axe or snow saw to hack some snow loose, then shovel out that material. Like coal mining, but cleaner. Aim to construct the entrance shaft lower than the main floor, so cold air will have a more difficult time coming in. Be careful not to make the roof too thin, as your body heat will cause melting and the whole thing could collapse. No concrete rules here, but probably a foot or thicker is the minimum. A small roof vent may be helpful for ventilation if you have several people inside.
You can add all the interior touches you wishbunks, shelves, a card table, you name it. To make that cave interior glow like the National Cathedral on Christmas Eve, get a Uco Candelier ($34; www.ucocorp.com), a three-candle setup that will give you enough light to read by, while adding a pleasant degree of warmth (although snow caves are astonishingly warm without). A good ground cover will also be useful, the best being something like the Space All-Weather Blanket ($12; www.rei.com). This will keep moisture out of your sleeping pads and, with shiny side up, will reflect warmth back into the cave.