New Delhi, April 7 -- Two months after the deadliest avalanche in modern California history, an analysis by leading U.S. experts questions the guides' decision to lead such a large group through dangerous terrain amid avalanche warnings.

The backcountry skiers were traveling in a tightly packed line when the tour leaders with Blackbird Mountain Guides should have spaced them out to reduce the risk, according to the report prepared by the Sierra Avalanche Center, which was published Saturday on the National Avalanche Center site.

"Exposing only one person at a time to avalanche terrain is an accepted best practice for backcountry travel," the report said. "Analysis of past avalanche accidents has indicated that larger group sizes (4 or m...