Powder Mountain Icefield facts for kids
The Powder Mountain Icefield is a huge area of ice and snow. It's also called the Powder Mountain Icecap or the Cayley Icefield. You can find it in the Pacific Ranges of southwestern British Columbia, Canada. It's about 20 kilometers (12 miles) west of Whistler and 90 kilometers (56 miles) north of Vancouver.
On one side of the icefield is the Squamish River valley. On the other side is the Callaghan Valley. This valley was used for the Nordic sports during the 2010 Winter Olympics.
Many volcanoes are found around the icefield. These include the active Mount Cayley massif. Other peaks are Powder Mountain, Brandywine Mountain, and Mount Fee. Mount Callaghan is a sleeping volcano just northeast of the icefield. Mount Brew is a mountain to its south.
Cool Facts About the Icefield
The Powder Mountain Icefield has seen many subglacial eruptions. These are volcanic eruptions that happen under the ice. When lava cools very quickly, it forms a lot of glass. This is why rocks like those at Ember Ridge and Slag Hill have so much glass.
The rocks here are mostly andesite and rhyodacite. They can have up to 70% glass!
How Volcanoes Form Under Ice
Imagine a volcano erupting under a thick icefield. The hot magma melts a path straight up through the ice. This creates a vertical tunnel. When the magma cools, it forms a large, solid block. Gravity then flattens the top of this block. This is how flat-topped, steep-sided volcanoes called tuyas are made. Slag Hill is an example of a tuya.
The most recent volcanic activity in this area happened less than 10,000 years ago.
