I-90 Snoqualmie Pass Road Conditions

Cross the Cascades on I-90 — know before Snoqualmie Pass closes. This guide introduces seasonal risks along the I-90 corridor. Open your route in TripCaptain to check the forecast, compare departure times and follow changes as you travel.

Winter Driving Pattern

Snoqualmie Pass is the snowiest stretch of any US interstate, and I-90 climbs straight through it — from North Bend at about 130 m (427 ft) to the summit at 921 m (3,022 ft) and back down to Hyak. In an average winter the pass takes 12–15 m (39–49 ft) of heavy, wet Cascade snow, and 23 avalanche paths cross the highway itself, making this the most actively avalanche-controlled corridor on the interstate system. When crews close the road for control work — which happens 10 to 20 times a season — there is no quick detour, and the next open crossing is hours away. Traction-tire and chain requirements are posted from roughly November through March, and even on clear days the shaded curves on the descent hold black ice at dawn and after dark. Conditions at the summit can differ sharply from the valley floor, so a departure that looks fine in North Bend can meet a whiteout at the top. TripCaptain checks the hazards along the corridor for your specific departure time, so you know before you leave whether to go now, wait, or hold until the pass reopens.

Common Hazards on This Corridor

• Avalanche-control closures: 23 avalanche paths cross the highway, and crews routinely close the road to trigger slides before they run on their own; the pass shuts 10 to 20 times a winter with no marked detour. The official pass status decides whether the road is open before you commit to the climb.
• Heavy wet Cascade snow: The summit takes 12–15 m (39–49 ft) of snow a year, and it falls fast and heavy; the road often requires chains or winter tires, and a single storm can bury the lanes in hours.
• Black ice on the shaded descent: Even after the snow passes, the shaded curves and bridges on the descent refreeze at dawn and overnight; the ice is hard to see and common from November through March.
• Whiteout at the summit: During snow squalls and wind, visibility at the summit can drop below 400 m (¼ mile) in minutes while the valley stays clear; slow down and add following distance well before you reach the top.

Frequently Asked Questions

Is I-90 over Snoqualmie Pass safe to drive in winter?

Most winter days it is open and drivable with the right preparation, but this is the snowiest interstate crossing in the country, so conditions change fast. Carry chains, use winter tires, cross in daylight, and check the official pass status before you leave — the road closes 10 to 20 times a season and there is no quick way around it.

How often does Snoqualmie Pass close, and why?

The pass closes roughly 10 to 20 times each winter, mostly for avalanche control across the 23 slide paths that cross the highway, plus heavy snow and crashes. There is no marked detour, and a closure can last from under an hour to most of a day, so check the official pass status before you commit to the climb.

Do I need winter tires or chains on I-90 at Snoqualmie Pass?

Yes. Traction-tire or chain requirements are posted on this stretch from about November 1 through March 31 and are enforced at the pass. Carry chains that fit your vehicle even outside those dates whenever snow is in the forecast for the summit, and be ready to put them on when the law is posted.

What is the best time of day and year to cross Snoqualmie Pass?

Aim for daylight, mid-morning to early afternoon, once overnight snow has been cleared and any control work is done; avoid dawn, when shaded curves hold black ice, and the hours during and just after a storm. Late spring through early fall is easiest, but snow can fall at the summit in any month. TripCaptain checks the hazards along your exact route and departure time and tells you the safest window to cross.

How high is Snoqualmie Pass and how long is the corridor?

The summit sits at 921 m (3,022 ft). The corridor climbs from North Bend at about 130 m (427 ft) up over the pass and down to Hyak — roughly 37 km (23 mi) with about 790 m (2,600 ft) of climbing — which is why the weather at the top can be far worse than at either end.

What should I carry, and what if I get stranded on the pass?

Carry chains, warm layers, a blanket, food, water, a charged phone, and start with a full tank or battery. If you are stopped by a closure or get stuck, stay with your vehicle, keep the exhaust pipe clear of snow, run the engine only in short bursts for heat, and wait for word that the road is open again rather than setting out on foot.

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