Here's why:

* Dormant: A dormant volcano is one that has not erupted recently but is still considered capable of erupting again in the future.

* Extinct: An extinct volcano is one that is unlikely to erupt again because it has lost its source of magma.

While Crater Lake was formed by a massive eruption around 7,700 years ago, it's not considered extinct. The volcanic system that created Crater Lake is still active, as evidenced by:

* Geothermal activity: There are hot springs and fumaroles (vents that release steam and gases) around the rim of the lake.

* Seismic activity: The area experiences occasional small earthquakes.

Although the chances of a major eruption in the near future are low, Crater Lake's volcanic system remains active, making it officially dormant, not extinct.