4-season and winter tents

4-season tents are particularly robust tents suited to difficult weather conditions, particularly in winter, including snow, wind and heavy rain, and to high-mountain bivouacs. 

These winter tents use highly waterproof fabrics, often 8 or 10,000 mm for the groundsheet, which insulate against moisture and cold and improve comfort in bad weather. The comfort of 4-season tents is enhanced by solid inner fabrics, which offer more protection than the mesh fabrics of ultralight tents.

Expedition tents often have 3 poles to reinforce the structure, highly durable fabrics and sometimes snow skirts.