Eleven of the thirteen volcanoes in the Cascade Range have erupted at least once in the past 4,000 years, and seven have done so in just the past 200 years. The Cascade volcanoes have had more than 100 eruptions over the past few thousand years, many of them explosive eruptions. However, certain Cascade volcanoes can be dormant for hundreds or thousands of years between eruptions, and therefore the great risk caused by volcanic activity in the regions is not always readily apparent.