The Volcano at the southern end of the Northern Cordilleran Volcanic Province just north of the Alaska-British Columbia boundary is probably the youngest in Canada. It is a poorly built cinder cone made of loose volcanic ash, lapilli-sized tephra and volcanic bombs. Lying above a remote mountain ridge in the Boundary Ranges of the Coast Mountains, it is responsible for lava flow eruptions in 1904 and older that traveled south through river valleys where they crossed the border into the U.S. state of Alaska and dammed the Blue River, a short tributary of the Unuk River. In doing so it formed several small lakes. This eruption had a massive effect on fish, plant and animal inhabitants of the valley, but there is no record of its impact on people, most likely because people were not in the remote area. The entire length of the lava flows are at least and still contain the original lava features from when they were erupted, including pressure ridges and lava channels. However, sections of the lava flows have collapsed into underlying lava tubes to form cavities. Tephra and scoria from The Volcano covers adjacent mountain ridges and even through it is very young, it has been reduced by erosion from alpine glacial ice found in the heavily glaciated Coast Mountains. The estimated volume of lava and ash from The Volcano is .