Washington state uses helicopter to cause avalanches

Here.

Excerpt:

SEATTLE, Feb. 4 (UPI) -- The Washington state Department of Transportation used a helicopter to drop explosives and trigger avalanches around Snoqualmie Pass for the first time ever.
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More than 6 1/2 feet of snow fell in the area over six days, creating avalanche possibilities in areas that haven't had an issue with the problem in 30 years, the Seattle Times reported Monday.