She was cheating and regulating her own body temperature, which was why she seemed so perky.  Normally she wouldn't use her Bene Gesserit talents in such a flagrant way, but it was only for an hour, and was hardly going to lead to Abomination.  "I hope you brought your mittens!  For those of you that didn't..." she knelt to open the first chest, which was filled with coats, hats, mittens, and snow shoes.  "Suit up." 

"Long before brick or wood houses with indoor heat became commonplace, people had to be creative when building homes to protect them from nature's elements," Ghanima lectured as people got dressed.  "Wealthy Europeans embraced the concept of a nearly indestructible castle built from stone. Native Americans in warmer climates favored the tepee, or tipi, made entirely of animal hides or bark.  Unfortunately, for the inhabitants of Earth's more frigid regions, such as the Canadian tundra, neither of these were good options. Building materials were pretty much nonexistent, making it difficult to craft even the most rudimentary home. These people used the only abundant material to form a modest roof over their heads: snow. Thus, the igloo was born. The Inuit, better known to some of you as Eskimos, invented the igloo centuries ago. The igloo was a means for hunters to survive brutal winters in a vast area spanning more than 3,500 miles, including eastern Siberia, Greenland, Alaska and parts of Canada." 

"Today, we will learn how to build the most basic of snow shelters," she continued.  "Knowing how to make a snow trench shelter, a snow cave, or igloo can save your life in a winter survival situation. The great insulative qualities of snow can be used to help keep you warm enough to survive in even the coldest weather; but only if you know how to use the snow to your advantage." 

"Only experts should try to make an igloo to spend the night in, least it collapse on you.  A snow trench or cave, however, almost anyone can do," Ghanima said, quickly explaining the techniques behind making a trench. "I've provided shovels and knives for today's work, but you won't always have such equipment in the field.  Snowshoes also make good digging tools, and if you're carrying a field kit, a cup or pot will also work." 

"Now get to work," she said, opening the second chest to distribute tools to the class before taking a knife for herself.  She wasn't going to ask the students to do something that she was unwilling to attempt herself.  "Feel free to work solo or in groups.  I programmed the room so that we've got one hour to dark, and you don't want to be caught out without a place to sleep."