cut in the most desirable spot. Time and effort are required to hollow out the center of a quinzhee, though these can be reduced by piling snow around a hollow structure, such as a tarp-covered pile of packs or a makeshift tent or dome. Melting and refreezing the inner side of the quinzhee can strengthen it, as it does an igloo; this can be done rapidly with a lamp or candle,, but body heat is also adequate. Allowing the interior temperature to rise above freezing point risks weakening the shelter significantly, especially if the outside air temperature is near freezing. A small hole for air circulation should be poked through the ceiling. To avoid dripping melt-water, irregular or bumpy surfaces are often smoothed to direct the flow of water down the walls to gather around the edges. A non-airtight fabric door cover will minimize the amount of cold air coming into the quinzhee. An empty, well built snow structure, 16 or more hours old, in weather below may be strong enough to support a group of adults standing on top of it. Dangers All snow shelters eventually collapse or melt. Quinzhees can collapse from poor snow conditions, warm weather, blowing rain, construction problems (hitting a supporting wall), failure to let the snow sinter long enough, or from people climbing on them. Collapse poses a danger of suffocation for occupants. Quinzhees should not be used when temperatures are warmer than due to risk of collapse. The greatest risk of collapse occurs during the excavation process. Longer sintering time generally reduces risk of excavation collapse. To reduce undue loading on the roof of the quinzhee, the interior ceiling should be excavated first, then the interior walls and floor. One person should be outside the quinzhee while another is digging inside. Place a shovel, branch, hiking pole, or such near the head of a sleeping person for roof support, to break a falling roof to create an air gap, and/or as a tool to dig out. One shovel should be left outside to mark the door and aid rescuers in digging occupants out. Some users prefer a marker to be left outside the quinzhee nearest the heads of sleeping occupants to indicate where rescuers should start digging. Lumitalos A lumitalo is a more elaborate snow-house or building made out of snow in a manner similar to a quinzhee. The term is Finnish in