Many Whistler locals may be familiar with Mount Garibaldi (or Nch'ḵay̓, named by the Skwxwu7mesh people of the Squamish Nation) and Garibaldi Park, but did you know Mount Garibaldi is actually a volcano?
Garibaldi Provincial Park is located along a small segment of the Pacific Ring of Fire called the Garibaldi Volcanic Belt. The belt was created by the collision of two tectonic plates, the Juan de Fuca Plate and the North American Plate. The history of the Belt began 4 million years ago with the eruption of Mount Cayley. The most recent eruption in the Garibaldi Belt was Mount Meager about 2,500 years ago.
Volcanoes like Mount Garibaldi are formed by repeated volcanic eruptions. Hot magma from the Earth’s core flows through a vent and then cools on the Earth’s surface. When high viscosity magma flows up the vent it creates a steep, rising cone shape because the lava cools too quickly to spread far from the vent. Mount Garibaldi is this type of volcano, known as a stratovolcano. Black Tusk is another example of a stratovolcano found in Garibaldi Park.
It is believed Mount Garibaldi’s last eruption occurred during the ice age, roughly 13,000 years ago. While that may sound like a long time, it is fairly recent in geologic time. For comparison, Black Tusk is thought to have last erupted roughly 170,000 years ago.
Mount Garibaldi’s most recent eruption resulted in half of the volcanic structure forming on top of the glacier. When the glacier melted, the western side of the volcano crumbled, creating landslides that spread rubble all throughout the Squamish Valley.
Volcanic activity has also created some of Garibaldi Park’s other striking features. The Table was formed between 10,000 and 15,000 years ago when volcanic activity disrupted the glacier. The melting ice slowed and confined the flowing lava, cooling it quickly. Pulled to the sides of the mountain by gravity, the lava formed a flat top, known today as The Table. More than 9,000 years ago lava flows blocked the valley, creating The Barrier that trapped glacial meltwater and formed what is known today as Garibaldi Lake. The glacial runoff causes the piercing blue colour of the lake.
Volcanoes can lie dormant without erupting for thousands of years and still not go extinct. Not to worry! If Mount Garibaldi became active again, we would be able to see warning signs such as seismic activity, hot springs, and hot spots as a result of the rising magma.
While we don’t know if Mount Garibaldi is done erupting for good, we do know visiting Garibaldi Park is a fantastic way to spend a warm summer day. Take the time to check out Mount Garibaldi and additional peaks, Atwell Peak and Dalton Dome. The area offers a variety of activities for its visitors, including hiking, biking and camping. While you are there make sure to check out Garibaldi Lake too!
Ella Healey is the Summer Program Coordinator at the Whistler Museum through the Young Canada Works Program.
