The Washington State Department of Transportation says a new remote-controlled system will replace the aging artillery once used to trigger avalanches over Snoqualmie Pass, marking a major safety and efficiency upgrade for one of the state’s busiest mountain routes.
For decades, avalanche control crews relied on military-grade weapons to fire explosive projectiles into unstable snowfields above Interstate 90.
The goal was to trigger small, controlled avalanches to prevent dangerous slides from burying the highway below.
The system, in use since the 1980s, included a World War II-era Howitzer, an M60 tank and a recoilless rifle.
WSDOT says while these methods worked, they were expensive, time-consuming and put crews at risk.
Preparing to fire could shut down the highway for up to six hours, and crews had to work just feet from explosives to complete their mission.
“Previously, my crew was less than a foot away from launching artillery systems,” said John Stimberis, WSDOT’s avalanche control supervisor for Snoqualmie Pass. “Now we’ll be able to force an avalanche in a controlled environment, potentially miles away.”
The transition away from artillery was made possible by one-time funding from the Washington State Legislature through Senate Bill 5161.
The new Remote Avalanche Control system—powered by solar panels—allows WSDOT to detonate charges remotely, without closing the highway for long periods or positioning staff in hazardous locations.
WSDOT says the benefits are significant. The new setup allows for faster response times, shorter closures, safer operations and longer system life.
What once took four to six hours can now be completed in as little as 30 minutes to two hours.
Unlike leased artillery, the new system belongs to the state and is expected to last at least three decades.
Snoqualmie Pass sees about 34,000 vehicles a day, including thousands of freight trucks.
Even short closures have statewide economic impacts, making the new technology an important step for keeping people and goods moving year-round.
Washington has already installed similar systems on Stevens Pass, and with eight remote avalanche systems now active statewide, it joins states like Colorado, Utah, and California in adopting the safer technology.
WSDOT’s avalanche team consists of three full-time and two on-call specialists who also use trams and helicopters to place explosives when conditions allow.
These options provide flexibility when storms or terrain limit access.
The agency emphasized that while the new technology will reduce risks and shorten closures, drivers still play a role in keeping passes open.
Most winter closures on cross-state routes like I-90, U.S. 2, and U.S. 12 are caused by drivers going too fast for conditions or ignoring chain-up requirements.
WSDOT partners with the National Weather Service, Northwest Avalanche Center and other agencies to forecast storms and direct plow crews where they’re most needed — a system known as “swarming the storm.”
Officials say the new system represents a safer, smarter approach to managing Washington’s winter mountain highways.
©2025 Cox Media Group
