Brian Stoecker
Turnagain Times Correspondent
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Brian Stoecker/Turnagain Times |
After months of foreplay, Mount Redoubt finally got serious. On Sunday, March 22 at 10:38 p.m., the 10,197-foot volcano across Cook Inlet, 100 miles SW of Anchorage, burst to life with a series of five eruptions over seven hours.
Super heated pyroclastic flows, descending upon the volcano’s glacial ice, created flash flooding on the Drift River, threatening an oil terminal in the river’s floodplain. Six million gallons of oil remain in the tanks to prevent destabilization due to buoyancy, in the event the facility’s levee is breached (Drift River is 80 miles from Turnagain Arm).
Ash from the initial events rose to 60,000 feet above sea level and traveled north, reaching Denali Park. Subsequent eruptions throughout the week also drifted south across the Kenai and west toward the Alaska Peninsula.
Then came our turn.
On Saturday, March 28, Redoubt placed Turnagain Arm in the crosshairs. One minute before the opening tip-off between Villanova and Pitt in the NCAA basketball tournament, Redoubt belched an acrid cloud of March madness to 35,000 feet. With five minutes left in the game, ash from the 3:29 p.m. eruption began falling upon south Anchorage as it advanced toward Turnagain Arm communities, turning the fresh blanket of snow to an eerie gray.
The eruption shut down the Anchorage airport. Vehicle traffic tapered as drivers parked and covered their cars to protect the engines, moving parts, windshields and paint from the abrasive ash. Pets were brought indoors. Anyone venturing outside without protective wear, returned with grit in their hair, eyes and mouth. A hint of sulfur wafted in the breeze.
Despite the ubiquitous ash, the event presented a limited risk to health and machinery. The particulates could enter the mouth but were large enough to prevent inhalation without a gasping effort. The ash was also too large to penetrate automobile air filters. The total accumulation over several hours was “trace”. A 10x12 foot tarp collected barely a cup of ash during the event.
Now would not be the time to change your air filter. An old filter that reduces airflow, also restricts ash flow. Check your filter for holes. If there are none, keep it.
The region’s last notable ash fall arrived courtesy of Mount Spurr in the summer of 1992. About 1/16 of an inch accumulated along Turnagain Arm while skirting Cooper Landing. The winds blew the ash into corners of walls and curbs, or miniature drifts, leading many to recall two inches.
Spurr’s ash remained prevalent for years and it’s rumored that deposits are still found in the Chugach.
Four Redoubt and St. Augustine eruption cycles over the past 33 years only deposited trace amounts of ash throughout the area. Some disrupted air traffic, as did Spurr. Mount Iliamna, the sleepiest of Cook Inlet’s four volcanoes, has been dormant since 1953.
In December 1989, Redoubt nearly downed a KLM 747 with 231 passengers aboard, after the plane flew through its distant lingering plume.
Ashen silica was sucked into the turbines, essentially encrusting the engine with glass, resulting in a flame out. The plane fell nearly 15,000 feet before the frigid air cracked the brittle coating and expelled it. Pilots restarted the engines, 5000 feet above the Talkeetna Range. The plane landed safely, but with $80 million of damage.
According to the Alaska Volcano Observatory (AVO), Redoubt’s alert level remains at “RED/WARNING” as eruptions continue on a regular basis. It will likely remain active for several months and could vent for years before returning to complete dormancy.
For regular Redoubt updates and related information such as ash fall and air quality advisories, go to the AVO web site at www.avo.alaska.edu.