Item: I-90 Snoqualmie Pass: Operating a Highway Avalanche Program During a Major Construction Project
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Title: I-90 Snoqualmie Pass: Operating a Highway Avalanche Program During a Major Construction Project
Proceedings: Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
Authors:
- John Stimberis [ Washington State Department of Transportation ]
Date: 2012
Abstract: Snoqualmie Pass, WA (921m) receives an average of 1100 cm of snowfall annually. Interstate 90 over Snoqualmie Pass is the major highway through the Cascade Mountains of Washington State, with traffic volumes averaging nearly 30,000 vehicles per day and peak volumes exceeding 50,000. Numerous avalanche paths affect I-90 in the vicinity of Snoqualmie Pass. Avalanche delays and closures have an economic impact that often exceeds several million dollars (USD), depending on the length of the closures. The area with the most active avalanche paths has a two-lane snow shed covering the westbound lanes; eastbound lanes are fully exposed to the avalanche hazard. Up to 40 avalanche control missions may occur at this site each winter. The existing two-lane snow shed will be replaced as part of a $550 million (USD) highway expansion project. Construction plans include replacing the existing snow shed with a larger shed or a bridge. Approximately 1500m of snow supporting structures will be installed in adjacent avalanche zones. The construction season runs from May through October and is suspended during the winter due to snowfall and avalanche hazards. The 6-month construction season will not allow enough time for demolition of the existing snow shed and construction of the replacement structures. Thus, the affected area will be left without avalanche defensive structures for one to two winters. In this paper we will examine the challenges and possible solutions that the WSDOT Avalanche Forecasting and Control program faces. In addition we will provide a more detailed look at the proposed structures and their impacts to the future of our highway avalanche program.
Object ID: issw-2012-547-552.pdf
Language of Article: English
Presenter(s): unknown
Keywords: snow sheds, avalanche fences, explosives tramways, avalanche forecasting, avalanche control
Page Number(s): 547-552
Subjects: hazard management highway safety explosives
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