When did Plateau peoples use smaller conical houses?

Plateau peoples used smaller conical houses during the summer months when families were engaged in nomadic foraging activities.1

These tepeelike, lightly built structures typically sheltered a single nuclear or three-generation family and were distinct from the larger, communal A-frame houses used as winter residences. While these dwellings were traditionally covered with mats made of tule, Plateau peoples later began using canvas as Euro-American goods became more available. Additionally, groups that traveled to the Plains to hunt bison utilized the tepee during those expeditions, eventually adopting it as a full-time dwelling as they became increasingly nomadic.1