We tagged along with an avalanche control crew this week on Snoqualmie Pass. We were escorted to Exit 47 on Interstate 90. We waited on the onramp as the Department of Transportation and the State Highway Patrol coordinated closing down the freeway. The second the crews got the go-ahead, we drove out onto the freeway. And within minutes the explosive guys set off the charge.
Our photographer recorded as the explosion sent shockwaves through the mountains and sent snow cascading onto the freeway. But we didn't have much time. Even though we wanted to take a few more shots, the avalanche control supervisor said we had to get back into our car and drive to the next detonation point. They weren't messing around.
We drove a mile or so to the next spot and again within minutes after we got out of the car the crews set off the controlled explosion. Snow plows that were standing by swooped in to sweep whatever snow landed on the freeway. Soon the supervisors radioed down the pass for troopers to get ready to reopen all lanes. The whole operation took about 20 minutes. The crews got in, detonated, plowed and got out.

Avalanche Supervisor Craig Wilbour said closing down the freeway periodically for 20 minutes beats having a natural avalanche dump snow across all lanes which could take more than two hours to clean up. And if preventing longer closures is not a good reason enough, Wilbour says, "it beats having the snow land on you."

By the way, check out the video. It's pretty cool to hear the loud boom and see the mountain shake and then the snow rumbling down.