Figure A20. Hoodoo Mountain Hoodoo Mountain, viewed looking northwest, rises above the surrounding valley of the Iskut River and flanking glaciers on this rare clear day in the British Columbia Coast Mountains. The flattened top of the volcano attests to the volcano's constant struggle with surrounding and overlying ice during its 100,000 year eruptive history. (Photograph by B.R. Edwards) larger image [JPEG, 15.7 kb, 400 X 262]

Hoodoo Mountain is a flat-topped volcano on the north edge of the Iskut River, about 100 km northwest of the town of Stewart, in northwestern British Columbia (Figure A20). The volcano has an ice cap 3 km in diameter and, throughout most its history, has been influenced by glacial ice. Most of the volcanic deposits at Hoodoo Mountain are lava flows; however, some pyroclastic rocks are also found, indicating at least one period of explosive activity. Most of the volcano was formed beneath glacial ice, and it has been overlain by glaciers or an ice cap for most of its eruptive history. All recent flows exposed on its flanks appear to have originated from beneath the existinf summit-covering ice. The edifice consists of a volcanic pile of fine-grained lavas interbedded with glass-rich breccia (hyaloclastite), both welded and nonwelded pyroclastic breccias, and highly crystal-rich (porphyritic) lava flows. Several of the youngest porphyritic lava flows have not been heavily glaciated.

Hoodoo Mountain volcano is in an area currently (1997) mined for gold and wollastonite, and several large mining camps are within 15 km of its south flank. Should there be renewed activity in the form of lava flows, damming of the Iskut River could be a significant hazard to current mining operations along the river. Mining infrastructure is located within the floodplain of the river and could be damaged by rising waters. Similarly, eruptions through the summit ice cap or onto the surrounding glaciers could also cause significant flooding of the Iskut River and the lower portion of the larger Stikine River. Although not as disruptive to mining operations, flooding of the Iskut and Stikine rivers could seriously disrupt the salmon fishery on the Stikine River. Air-fall tephra from an explosive eruption could disrupt local mining operations and any airborne ash would disrupt air traffic to and from the mining camps. High ash columns would disrupt air traffic between Canada, Alaska, and Asia.