A volcano that erupted under a glacier. Because volcanic activity in western Canada was contemporaneous with the ebb and flow of Cordilleran glaciations, many of the volcanoes display ice contact feat
ures. Mount Garibaldi itself is a supraglacial volcano which erupted onto a regional ice sheet. Others, such as Hoodoo Mountain, were contained within basins thawed in the ice and assumed the flat-topped form of tuyas. Still others, such as the subglacial mounds of the Clearwater Field, were erupted under glacial ice to form piles of pillow lava and hyaloclastite.
The diffused light from the sky when the Sun is below the horizon, either from daybreak to sunrise or, more commonly, from sunset to nightfall. There are three types of twilight: astronomical twilight
, civil twilight, and nautical twilight. They are divided on the basis of the solar depression angle.