Throughout the Pleistocene epoch 1.6 million to 10,000 years ago, volcanism in the Northern Cordilleran Volcanic Province was broadly associated with glacial ice and ice sheets during glacial periods, including the large Cordilleran Ice Sheet. This volcano-ice association can be recognized in three different physiographic settings, each displaying unique relationships between topography, volcanism and glacial ice. The first volcano-ice interaction is displayed as tuyas, including Tuya Butte, on the Tanzilla Plateau in the Northern Interior of British Columbia. This sub-section of the Stikine Plateau consists of large flatlands with hills of low relief, and might have been one of the areas of ice accumulation for the Cordilleran Ice Sheet. Tanzilla Plateau volcanism throughout the Pleistocene epoch was basaltic subglacial eruptions. The most generally known subglacial volcanoes are distinctive tuyas, which commonly reach more than in elevation. Other volcanic forms also exist, some of which are basic and others that are probably the products of weathering. The subdued relief on the Tanzilla Plateau strongly influenced edifice morphologies, favoring broad-based tuyas. The hydrological conditions in these areas likely were controlled by relatively uniform ice thickness and gentle topography.