Alaska | Avalanche | Pipeline Hazards

In a previous post, I pointed out that Alaska experienced record warmth for the month of January 2014. This image shows water vapor in the atmosphere as blue, white, and green flowing toward Alaska on January 23, 2014 from the south. Yellow is dry air. The warm moist flow had persisted for several days and gave some parts of Alaska 12″ of rainfall in less than two weeks. This atmospheric river phenomenon is sometimes called the Pineapple Express. At the same time, this part of the Jet Stream arced toward the southeast and brought cold arctic air to the eastern half of the country. This pattern has persisted most of the winter. Currently, the Jet is entering the coasts of Washington, Oregon, and northern California with some welcomed precipitation.

University of Wisconsin

I also pointed out that avalanches were a significant problem caused by the excess rainfall. The port of Valdez was cut off from the mainland on January 24 when a massive avalanche buried Richardson Highway Route 4 to the east of the city. The mound of snow was 120 feet (40 meters) deep in places and up to 1,500 feet (460 meters) long. The road was finally cleared February 5th after two weeks of closure and opened for traffic not long after.

Robert Dunning and staff, Alaska DOT&PF

Valdez is marked by the red square in the top image. I was curious exactly where the city is located and how the road and geography were arranged. So, I opened Google Maps and started exploring.

This video captures of the movements on my screen and adds a few annotations. Highway 4 is the only road access for the town. The airport remained open. Valdez is located with excellent access to the ocean for tankers carrying oil from the terminal of the Trans Alaska Pipeline System (TAPS). The avalanche temporarily blocked the Lowe River creating a lake. A previously constructed aqueduct allowed it to drain quickly. The avalanche debris did not quite reach TAPS. Fortunately, it is underground at that location and secure from avalanche damages. The video does not use current satellite imagery.

Google Maps screen capture

Wikimedia Commons

The Trans Alaska Pipeline System is a 48″ diameter pipe that runs 800 miles from Prudhoe Bay to Valdez. It was built between 1973-1977 highlighted in this dated video. The 1973 oil crisis was a strong stimulus for construction of TAPS. In crossing the entire state of Alaska, the pipeline encounters numerous hazards and challenges. Among them are caribou migration, extreme cold followed by summer heat, snow, permafrost, 34 major river crossings, earthquake fault lines, and avalanches. It faced much opposition. Some interesting facts about TAPS.

In order to mitigate the avalanche hazards, sections of the length of TAPS are underground. Such is the case near the Valdez avalanche above. Of the 800 miles of pipeline, 380 miles are buried.

In order to minimize earthquake damages at four fault line crossings, the pipeline was designed in a sort of zig-zag layout. Movements of the ground were to be absorbed by the more flexible nature of this design and prevent ruptures and spills. On Nov. 3, 2002, the pipeline withstood a magnitude 7.9 earthquake with an estimated 18 ft horizontal and 2.5 ft vertical movement.

Photo courtesy of Jeffrey Kargel

This image also shows the heat radiators in white on top of the support posts. They are designed to carry heat from the permafrost layers below ground up to the surface and dissipate it into the air. The passive system prevents melting of the permafrost and sagging of the supports to the pipeline.


Even with the best of engineering and construction, TAPS is vulnerable to incidents of spillage. You can read about several instances in that link. It continues to supply crude oil. In 1988, it peaked in supply to the U.S. at 25% of our needs. Today, it supplies 17% of U.S. needs. How much of the production goes to other buyers, I do not know. Personally, I hope our dependence on crude oil and other fossil fuels decreases. It would please me to see the end of the North Slope fields and TAPS in the future.


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5 thoughts on “Alaska | Avalanche | Pipeline Hazards

  1. Pretty impressive avalanche to take that long to clear. Your mention of heat dissipators to protect the permafrost reminds me of some photos I saw recently of houses undermined by melted permafrost. That thawing is a really serious effect of climate change, esp as it is happening so fast up there. The atmospheric changes alone…
    It is great to see a Pineapple Express finally dump some precip on Calif now. Drop in the proverbial bucket but oh so welcome, esp the snowfall.
    Thanks for the tour of that part of the arctic.

    Like

    • Good evening.

      The melting permafrost under houses is a serious problem. Another is the methane released by the warming and thawing. And, methane is several time worse than CO2.

      The rains are really welcome in the west. They don’t seem to be making it very far down into southern part of California. The produce growing areas are being missed.

      I’m glad you stopped by.

      Like

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