Geologists monitoring Mount Redoubt for signs of a possible eruption noticed that a hole in the glacier clinging to the north side of the volcano had doubled in size overnight — and now spans the length of two football fields.
Scientists with the Alaska Volcano Observatory on Friday flew close to Drift Glacier and spotted vigorous steam emitted from a hole on the mountain. By Saturday, they had confirmed the area was a fumarole, an opening in the earth that emits gases and steam, that was increasing in size at an alarming rate.
They also saw water streaming down the glacier, indicating heat from magma is reaching higher elevations of the mountain.
“The glacier is sort of falling apart in the upper part,” research geologist Kristi Wallace said.
The signs of heat add to concerns that an eruption is near, which could send an ash cloud about 160km northeast toward Anchorage, the state’s largest city, or onto communities on the Kenai Peninsula, which is even closer to the mountain on the west side of Cook Inlet. It would be the first eruption since 1990.
Particulate released during an eruption has jagged edges and can injure skin, eyes and breathing passages. It can also foul engines.
A week ago, the observatory detected a sharp increase in earthquake activity below the volcano and upgraded its alert level to orange, the stage just before full eruption. The warning that an eruption was imminent caused a rush on dust masks and car air filters in Anchorage.
Geologist Jennifer Adleman said the observatory has been recording quakes up to magnitude 2.1 but not at the frequency that preceded the last two eruptions in 1989 and 1990.
“We’re looking for an increase of seismicity to match the precursor activity,” Wallace said. “We haven’t seen that yet.”