Snoqualmie Pass Snow Depth & Snowpack: A Complete Guide

Snoqualmie Pass is the most-traveled mountain pass in Washington State. Interstate 90 carries roughly 29,000 vehicles per day over its 3,015-foot summit, making snow conditions here a daily concern for commuters, truckers, and skiers alike. Whether you’re planning a day at the Summit at Snoqualmie, checking road conditions before driving east, or tracking snowpack for backcountry travel, understanding how to read Snoqualmie Pass snow data will help you make better decisions.

Where Snoqualmie Pass snow depth is measured

The primary snow measurement site near Snoqualmie Pass is the Stampede Pass SNOTEL station (#788), operated by the Natural Resources Conservation Service (NRCS). The station sits at 3,850 feet elevation in King County, approximately 12 miles south-southeast of the Snoqualmie Pass summit. It has been recording daily snow depth, snow water equivalent (SWE), and temperature data continuously since October 1979, giving us over four decades of snowpack records.

Stampede Pass is not located at the Snoqualmie Pass summit itself, but at a nearby location in the same elevation band and precipitation zone. The readings are widely used as a proxy for snowpack conditions across the central Cascades I-90 corridor, including the ski areas at Snoqualmie Pass and the surrounding backcountry.

How much snow does Snoqualmie Pass get?

Snoqualmie Pass receives substantial precipitation. According to long-term climate records, the pass area averages over 100 inches of total precipitation annually, with snowfall averaging over 400 inches per season. Peak snowpack at Stampede Pass typically reaches around 140 inches of depth in mid-March, though this varies considerably from year to year.

Snoqualmie Pass has the lowest elevation of the three major east-west mountain passes in Washington that are kept open year-round (the others being Stevens Pass on US-2 and White Pass on US-12). This relatively low elevation means the snow line is closer to the pass summit, and Snoqualmie is more sensitive to storm temperature than the higher passes. A storm that delivers heavy snow at Stevens Pass may bring a mix of rain and snow at Snoqualmie, particularly at the lower base areas of the ski resort.

Understanding Snoqualmie Pass snow reports

When checking Snoqualmie Pass snow conditions, there are several data points worth understanding. Snow depth tells you the total height of the snowpack on the ground. Snow water equivalent (SWE) tells you how much liquid water that snowpack contains. The ratio between SWE and snow depth gives you snow density, which indicates whether the snowpack is light and fluffy or heavy and consolidated.

Recent snowfall is calculated by comparing today’s snow depth to previous days. Cascade Snow’s Snoqualmie page shows 24-hour, 48-hour, and 72-hour new snow totals, computed as the sum of each day’s positive depth gains. This method ensures that the 72-hour total is always equal to or greater than the 48-hour total, even when settlement occurs between readings.

Historical rankings put the current season in context. The Stampede Pass SNOTEL record spans over 45 seasons, so you can see at a glance whether the current year’s snowpack is above or below average for the date, and how it compares to every prior season on record.

Skiing at Snoqualmie Pass

The Summit at Snoqualmie is the closest ski area to Seattle, located directly at the I-90 interchange. It consists of four interconnected base areas: Alpental, Summit West, Summit Central, and Summit East. Alpental, on the north side of the highway, is known for its steeper terrain and backcountry access gates. The other three base areas sit on the south side and offer a broader range of beginner and intermediate terrain, night skiing, and terrain parks.

Because of its proximity to Seattle and its relatively low elevation, Snoqualmie sees heavy traffic on weekends and is highly sensitive to warm storms. Checking the current snowpack and the freezing level forecast before heading up can save you from a wasted trip during marginal conditions. The Snoqualmie snow page on Cascade Snow shows forecasts at base, mid-mountain, and summit elevation zones, so you can gauge whether precipitation will fall as snow or rain at different altitudes.

I-90 pass conditions and road travel

For the thousands of people who drive over Snoqualmie Pass daily, snow conditions directly affect travel safety. WSDOT monitors the pass continuously and posts chain requirements and closures on their Snoqualmie Pass travel page. Checking the current snow depth and forecast before driving helps you prepare for winter driving conditions, bring chains when needed, and avoid the pass during heavy storm cycles when closures are likely.

Significant snowfall at the Stampede Pass SNOTEL station correlates with challenging driving conditions on I-90. When the SNOTEL shows 6+ inches of new snow in 24 hours, expect reduced speeds, chain requirements, or potential closures. The snowfall comparison tool on Cascade Snow lets you check multiple weather model forecasts to gauge how much snow the next storm may bring.

Tracking Snoqualmie Pass snowpack after the NWRFC

For many years, outdoor recreationists and water managers tracked Snoqualmie Pass snowpack using the Northwest River Forecast Center’s (NWRFC) snow depth and density graphs. These plotted the current season’s SNOTEL readings against historical averages in a clear visual format. In June 2025, the NWRFC discontinued those graphs.

Cascade Snow’s Snoqualmie Pass page serves as a free replacement, providing the same historical context through interactive charts that show the current season alongside every prior year on record. The page also adds features the NWRFC graphs never had: multi-elevation forecasts, wind data, new snow density analysis, and a snowfall comparison tool covering multiple weather models.

Where to check Snoqualmie Pass snow depth

The Snoqualmie Pass snow report on Cascade Snow is updated daily with fresh SNOTEL data. It shows current snow depth, SWE, recent snowfall, historical season rankings, and 5-day weather forecasts at three elevation zones. For broader comparisons, the snowfall comparison page lets you see how Snoqualmie’s forecast stacks up against other Cascade passes like Stevens Pass and White Pass.