Yukon officials on high alert for Alaska volcano

Yukon officials are on high alert following reports that Alaska's Mount Redoubt could soon erupt. "Heightened unrest" prompted the Alaska Volcano Observatory, on January 25, to report that the mountain could erupt within...

Yukon officials are on high alert following reports that Alaska’s Mount Redoubt could soon erupt.

“Heightened unrest” prompted the Alaska Volcano Observatory, on January 25, to report that the mountain could erupt within “hours or days.”

Yukoners need not worry about waking up to find their backyards filled with lava, but keeping an eye on Mount Redoubt, about 180 kilometres to the southwest of Anchorage, is critical to protecting overflying aircraft, said Michael Templeton, manager of the Yukon Emergency Measures Organization.

Volcanic ash plumes are invisible to aircraft, but pose extreme danger to jet engines.

“It might look like a wispy cloud,” said Charlie Roots, a Yukon-based researcher with the Geological Survey of Canada.

“It’s nearly invisible—it’s not something like smoke that you can just fly around,” said Templeton.

Composed of fine-grain ash particles, the clouds can immediately clog up aircraft engines, causing them to stall.

In 1989, all four engines of a KLM jumbo jet shut down after the aircraft passed through a smoke plume from the erupting Mount Redoubt.

The jet plummeted four kilometres before crew members were able to reignite two of the engines and make an emergency landing at Anchorage Airport.

Upon inspection, the engines looked “like they had been sandblasted,” said an official. Repairs cost more than million.

When Indonesia’s Mount Galunggung erupted in 1992, a British Airways jet plunged eight kilometres before the crew regained power and made an emergency landing in Jakarta.

Nine days later, a Singapore Airlines jet suffered exactly the same fortune.

An eruption similar in scale to that of 1989, “appears to be the most probable outcome at this time,” said a statement by the Alaska Volcano Observatory.

Observers can therefore expect a plume 12 kilometres high and pyroclastic flows—fast-moving clouds of gas and hot ash—decimating an area within 15 kilometres of the mountain.

Less likely is the possibility of either a failed eruption, a much larger eruption or a complete collapse of a flank of the mountain, sending rock and debris tumbling into nearby Cook Inlet.

The “complete collapse” scenario only happens every 5,000 years, noted the observatory.

Far from any populated area, Mount Redoubt poses no immediate threat to human settlements.

However, nearby roads and communities, including Anchorage, could be subject to “ash fall,” a phenomenon where it literally snows volcanic dust.

The 1980 eruption of Mount St. Helens blanketed more than 57,000 square kilometres of the Pacific Northwest, with communities 500 kilometres away receiving more than a centimetre of ash.

Portions of the Alaska Highway were closed due to low visibility after a 1992 eruption in the Wrangell Mountains covered the road in ash.

Yukon communities could suffer some ash fall, depending on the height and direction of the plume.

Until it erupts, the exact effects won’t be known, said Templeton.

Contact Tristin Hopper at