In a sense, AEL&P had inherited the line's avalanche vulnerability from a previous generation. When the line was built in the early 1970s, diesel fuel was both a cheap and reliable backup power source. Snettisham was built according to an accepted standard of care, and never rerouted or retrofitted with diversion structures (nor were other preventive measures taken — such as vigilant avalanche control — to prevent avalanches from taking out any part of the line) because of the low probability of catastrophic avalanches. By and large, this strategy worked. There were only three documented outages caused by avalanches along the line. However, the two recent slides have obviously changed the utility's thinking.

AEL&P has embarked on a systematic effort to identify a long-term solution to protect the line from future outages and to build redundancy and reliability into the isolated transmission system. After the first slide last year, AEL&P worked continuously through last summer, the fall and this past winter consolidating existing data about the Snettisham line, digitizing and modeling drawings previously in paper format. AEL&P even initiated a LIDAR aerial survey to gain detailed information about the line. (Unfortunately, LIDAR surveying efforts were hampered because of inclement weather over the summer and fall, and final surveying wasn't completed until the first part of December.)

AEL&P also plans to hire an avalanche consultant to provide a detailed assessment of avalanche threats, forces and characteristics along the entire Snettisham line to develop practical avalanche-mitigation strategies. In time, the utility will assemble a report that assesses every possible solution, soliciting input and comments from the public in this process.

Current solutions on the table include diversion structures, breakaway conductor, reroutes to less avalanche-prone locations, a submarine cable in the waterway below, diversification of new generation sites (including hydroelectric power at Lake Dorothy) and more. Not a single option has been ruled out.

Determining and implementing a long-term solution will not happen overnight. The smartest and most economical solution will only be identified once records for the entire length of the line are modernized and threats to the line are better understood. In the meantime, in a place like Alaska, AEL&P is prepared for the worst-case scenario every day.

Eric Eriksen (eric.eriksen@aelp.com) is vice president of transmission and distribution for Alaska Electric Light & Power Co. During his 10-year term, he has worked on such projects as the Southeast Submarine Cable Intertie Project and Cruise Ship Shore Power Project, and has served as the project manager for both of the Snettisham avalanche-repair projects. He holds a BSEE degree from the University of Alaska and is actively enrolled in its MBA program. He is a licensed electrical engineer in Alaska.

Dan Zacharda (dzacharda@powereng.com) is a transmission line project engineer with POWER Engineers Inc. In his 15-year-career, Zacharda has worked on underground and overhead transmission and distribution projects across the United States. He holds a bachelor's degree in civil engineering from the University of Washington.

Jim Multerer (jmulterer@powereng.com) is a construction manager at POWER Engineers Inc. He has worked with POWER for 10 years on major projects in Texas, Alaska and Wisconsin, and has worked for contractor and consulting engineer firms for more than 35 years. Along with an accounting and computer background, he has managed multiple high-voltage power line construction projects in the United States.

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