|
Snoqualmie Pass is a mountain pass that carries Interstate 90 through the Cascade Range in the U.S. State of Washington. The pass summit at an elevation of is on the county line between Kittitas County and King County. Snoqualmie Pass is the largest of the three east-west mountain routes across Washington State that are kept open year-round, along with Stevens Pass (US 2) to the north, and White Pass (US 12) to the south. I-90 is the primary commercial artery between Seattle and points east, carrying an average of 29,000 vehicles through the pass per day.〔(WSDOT - Annual Traffic Report ) Accessed 2015-08-31〕 The pass lends its name to a census-designated place (CDP) located at the summit (see: Snoqualmie Pass, Washington). Both the CDP and Snoqualmie Pass are named after the Snoqualmie people of the valley to the west. == Weather == Snoqualmie Pass as it climbs into the Cascades passes through a micro-climate characterized by considerable precipitation, and at times hazardous conditions for travelers. The average annual precipitation is over 100 inches; snowfall averages over 400 inches. The average annual number of days with measurable precipitation is over 170. The rapidly changing conditions require special cautions, relayed to motorists via variable message displays along I-90.〔(Smarter Highways 102: Variable Speed Limits )〕 Depending on traction they may call for tire chains to be installed, usually on large trucks but occasionally on smaller vehicles as well. Chain-up areas are provided along the side of the Interstate to facilitate the placement of chains. The pass has been subjected to closures when weather conditions become extreme.〔(Snoqualmie Pass reopens after hours of closure - KOMO News )〕 A snow shed, constructed in 1950 when the road was known as US-10, formerly covered the westbound lanes, but it has been replaced by 'avalanche bridges', as of April 2014.〔http://www.wsdot.wa.gov/Projects/I90/SnoqualmiePassEast/HyaktoKeechelusDam/SnowshedRemoval.htm〕 The use of sheds (very rare on Interstates) is an admission that plowing cannot keep up with snowfall and avalanches. WSDOT maintains cameras at selected locations along the pass to monitor weather conditions. Some of these cameras can be viewed via the internet.〔(WSDOT - Snoqualmie Pass Road and Weather Conditions )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Snoqualmie Pass」の詳細全文を読む スポンサード リンク
|