KELLOGG, Idaho (AP) — An avalanche at an Idaho ski resort that killed three people last week was triggered by skiers, despite the efforts of the ski patrol to mitigate the danger, according to a preliminary investigation.

The Idaho Panhandle Avalanche Center said the ski patrol had taken steps on Jan. 7 to prevent avalanches at the Silver Mountain Resort near Kellogg, Idaho.

''They had done their control work just like they always do," Jeff Thompson, the director of the avalanche center, told The Spokesman-Review newspaper. "In fact, I think they did more than they normally do to open that slo...