Denali, Alaska, USA (oil pipeline, retreating glacier, micro-climate)


Thanks to Jane for sending this postcard from Denali, the highest peak in North America. Denali was formerly known as Mount McKinley until its official renaming in 2015. Its summit rises 6, 190 metres above sea level and the first verifiable successful ascent was made in 1913 by Hudson Stuck, Harry Karstens, Walter Harper and Robert Tatum.

Denali is high enough to create its own local weather and the peak is usually cloaked in cloud. The lowest temperature to have been recorded at the Denali weather station is −83.4 °C; even in summer the windchill has resulted in a low of −50.7 °C.

The pipeline shown on the postcard is the Trans-Alaskan Pipeline which transports crude oil from the north coast to the terminal at Valdez, helped by pumping stations along its length which maintain the oil’s momentum. Even so, it takes nearly 12 days for oil to travel the entire 1, 287km length. The pipeline has to be above ground because of the permafrost ground below. Permafrost ground is soil, sediment and rock that remains continuously frozen for at least two years.


Location of the Trans-Alaska Pipeline, PS shows pumping stations. (Photo: Creative Commons)


Also shown on the postcard is the Worthington Glacier. Like other glaciers, the Worthington is retreating, and has been doing so for around 150 years.