A tuya is a volcano that erupts under glacial ice. As the lava erupts it cools quickly. If the volcano breaks through the ice, a cap of pillow lava forms on the top. The shape left when the ice sheets recede is a steep sided, flat-topped hill (or mountain). There are 6 of these in Wells Gray and they are somewhat unremarkable in the landscape. The one that is easiest to see is McLeod Hill, to the east of Helmcken Lodge. It last erupted 12 000 years ago under the ice. Today, a ski trail goes up the slopes, part of the loppet route. It is also a bike route in the summer.

The tuyas of the area are part of the Wells Gray Volcanic Field, 21 volcanoes that have have cinder cones, mounds, hills, and tuyas for us to explore. Another good reason to visit this wonderful park.