The final phase of eruptive activity was effusive in nature with no explosive activity (VEI-0). This effusive volcanism produced lava flows with well-preserved lava channels on the northwest and southwest flanks of Hoodoo Mountain in the early Holocene epoch and are largely unglaciated, suggesting the final eruptive phase occurred in an ice-free environment. These lava flows originated from the mountain's flat-topped summit and volcanic vents on its flanks. Geologists do not always agree on the dates of these more recent eruptions, some dating them to nine thousand years ago, others to as recently as seven thousand years ago.