Redoubt Volcano eruption; Cook Inlet, Alaska

Cook Inlet, Alaska | 2009-Mar-23

Initial Notification: Redoubt Volcano, intermittently active since January and approximately 100 nm SW of Anchorage on the west side of Cook Inlet, resumed its activity late Sunday night and early Monday morning, March 22 & 23, with five explosive eruptions. These eruptions caused lahars, extensive fllooding, and mud flows around the Drift River Tank Farm, where oil from the Cook Inlet fields is temporarily stored prior to shipping out aboard tankers. Currently, two of the four active tanks have 74,000 bbls of oil apiece. At 7:30 PM on March 23rd, ADEC and USCG conducted an over-flight to determine any potential threat to the tank farm and related facilities at the Drift River Terminal. They observed extensive flooding to the area with mud flows to a depth of six feet in the area of the runway and ballast tank, but no significant penetration of the 18 to 20 foot high teritiary containment berm around the tank farm. No oil or hazardous substance releases have been reported at this time. Cook Inlet Pipeline Company, operator of the tank farm, is planning on-the-ground evaluation today of the teritiary berms, pumps, and other equipment and facilities necessary for the operation of the tank farm. The Alaska Volcano Observatory is predicting additional explosive activity of the volcano in the near future, which combined with the extensive amount of snow and ice on the flanks of Redoubt could cause additional significant flooding and mud flows towards the Drift River Tank Farm. The Coast Guard has asked the NOAA SSC to keep fully abreast of the situation and to participate in conference calls among the CG, the state, the tank farm operator and others. The last major explosive eruption of Redoubt volcano occurred on April 4. It was the largest eruption, during this sequence, and produced the largest lahar to date, completely encircling the Drift River Tank Farm (DRTF). None of the mud or water, however, penetrated the large dikes around the facility. As an additional safety precaution, Chevron and Cook Inlet Pipeline decided to completely shut in the DRTF and proceeded to draw down the oil in the two active storage tanks to minimal levels. To achieve greater tank stability, 30,000 Bbls of fresh water was added to each of the two active tanks. With no eruptions since April 4 and dome building in the volcano's throat dramatically decreasing, the Alaska Volcano Observatory (AVO) decided to downgrade the threat level of the volcano from orange to yellow on June 29, 2009.