trigger slides when they were still small???

[Anthony_1000]

Dear all,
I came across the following sentence in a passage in a TOEFL preparation book (TOEFL Reading Flash, p.20). I cannot understand the underlined part. I'd be very grateful for help.

Anthony

"It was Nature, however, who had the final say, delivering avalanche after avalanche over cabins, snow deflection barriers, and even a platform-mounted gun that was meant to trigger slides when they were still small."

 

[Tdol]

I think it means that the gun was meant to create small avalanches to prevent bigger ones forming, but nature still managed to cover the gun. In other words, people could do little to stop the power of avalanches.

 

[andrewg927]

In mountain towns, sometimes you will see guns that are attached to a platform that are used to create small avalanches (or to trigger slides).