I-90 is the primary commercial artery between Seattle and points east, carrying an average of 29,000 vehicles through the pass per day.

The Snoqualmie Pass foothills (below ~1-2000 ft elevation)[5] have a Csb (warm-summer mediterranean) climate, but climbing higher into the Cascades advances through a microclimate (warm-summer mediterranean continental, Dsb) characterized by considerable precipitation, especially during winter, and at times hazardous conditions for travelers.

[6] The rapidly changing conditions require special cautions, relayed to motorists via variable message displays along I-90.

[8] Depending on traction they may call for tire chains to be installed, usually on large trucks but occasionally on smaller vehicles as well.

Also in the summer and fall, paragliders and hang gliders may be seen flying above the valley, along the ridge and landing at Lake Keechelus.

Hudson's Bay Company trappers and traders were active in the Snoqualmie and Yakima valleys during the early 19th century.

[14] Captain George B. McClellan and his lieutenant Abiel W. Tinkham explored the Snoqualmie Pass region in 1853 and 1854.

Van Bokkelen, then of the Washington Territory Volunteers (militia), crossed Snoqualmie Pass on a scouting mission.

The rail line was abandoned 45 years ago in 1980, and the tunnel is currently a multi-use trail for bicyclists and hikers, part of Iron Horse State Park.

[18] On June 24, 1946, seven players on the Spokane Indians minor league baseball team, and their manager, were killed when their bus veered through a guard rail on the Snoqualmie Pass Highway and plunged down a 500-foot embankment and into a ravine.

[20][21][22] Since 1991, the Mountains to Sound Greenway Trust has acted to protect the scenic value of the I-90 corridor over Snoqualmie Pass.