MileCheckWhy does Snoqualmie Pass close so often in winter?
Snoqualmie Pass closes most often for avalanche control. WSDOT shuts I-90 near the summit, clears every car out, and sets off avalanches on purpose so they don't land on traffic, which usually takes 30 minutes to two hours.
Heavy snow, spinouts, crashes and vehicles without the required chains or traction tires close it too. (WSDOT) Check the live status on our Snoqualmie Pass page or Washington road conditions before you leave.
What happens during an avalanche closure?
- Crews close the road. A sweeper vehicle drives the zone to make sure no one is left in it.
- Explosives go on the slopes. Cable trams or artillery deliver them to the top of the avalanche paths. WSDOT now uses a 105mm howitzer when artillery is needed.
- Plows clear the road. Any snow that reached I-90 comes off before it reopens.
WSDOT says the typical delay is 30 minutes to two hours. In severe conditions it can be several hours. (WSDOT)
Why does it happen so often?
Snoqualmie and Stevens average more than 450 inches of snow each winter, and avalanche control runs all season on I-90. The most persistent avalanche zone is on the west side of the pass. (WSDOT) The summit sits at 3,022 feet, about 52 miles east of Seattle.
Traffic makes every closure bigger. WSDOT counts about 28,000 vehicles a day over the pass, about 5,600 of them freight. (WSDOT) A two-hour hold backs that up for miles on both sides.
What time of day does WSDOT close it?
There is no fixed hour. Crews try to work at night or when traffic is light, but the weather decides. (WSDOT) Planned closures go out through the WSDOT mobile app. WSDOT ended its separate I-90 text alerts on August 31, 2026. (WSDOT)
Can a chain sign close the pass?
Indirectly, yes. A car without chains that spins out on the climb can block lanes for everyone. Ignoring a posted traction tire or chain requirement carries a $500 penalty. (RCW 47.36.250) Vehicles over 10,000 lb must carry chains on I-90 between North Bend at MP 32 and Ellensburg at MP 101 from November 1 to April 1. (WAC 204-24-050) Our chains required guide covers what each sign means.
How do I know if Snoqualmie Pass is closed right now?
- Read the pass report for your direction. WSDOT posts eastbound and westbound separately at wsdot.com. MileCheck reads the same WSDOT feed on our Snoqualmie Pass page.
- Look at the summit camera. A camera shows snow on the road. It does not tell you if the road is open, so read the report too.
- Fuel up before the climb. North Bend going east, Easton or Cle Elum going west. A closure can hold you for hours.
In September 2026, before snow, MileCheck logged 53 events on I-90 in Washington, mostly construction. Winter counts go in our monthly road report.
What is the detour if I-90 is closed?
US 2 over Stevens Pass to the north, or US 12 over White Pass to the south. Both have their own snow, chain rules and closures. Neither is a short detour. (WSDOT) Often the fastest choice is to wait in North Bend or Cle Elum.
See the closure before you reach it
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Questions, answered
Why does Snoqualmie Pass close so often in winter?
Mostly avalanche control. Crews close I-90 near the summit, clear every vehicle out of the zone, then set off avalanches with explosives before snow can fall on traffic. WSDOT says the typical delay is 30 minutes to two hours. Heavy snow, spinouts, crashes and vehicles without required chains or traction tires also close it.
How long does a Snoqualmie Pass avalanche closure last?
WSDOT says 30 minutes to two hours is typical. In severe conditions a closure can last several hours, because crews have to clear any snow that reached the road before it reopens.
What time does WSDOT do avalanche control on I-90?
There is no fixed time. Crews try to work at night or when traffic is light, but the weather decides when control is needed.
How do I find out if Snoqualmie Pass is closed?
Read the WSDOT Snoqualmie Pass report for your direction, or open the WSDOT mobile app and turn on Snoqualmie Pass I-90 notifications. WSDOT ended its I-90 text alerts on August 31, 2026.
What is the fine for ignoring a chain sign on Snoqualmie Pass?
$500 under RCW 47.36.250 for failing to obey a posted traction tire or chain requirement.
What is the detour if Snoqualmie Pass is closed?
US 2 over Stevens Pass to the north or US 12 over White Pass to the south. Both are mountain passes with their own closures, and neither is a short detour.
Checked against WSDOT and Washington state law on October 15, 2026. Conditions change by the hour, so check the live feed before you drive.