One of three young boys buried in up to 10 feet of snow when an avalanche thundered down a Colorado mountain Sunday has died, authorities said Monday.

A nursing supervisor at St. Mary's Hospital said Taylor Huddleston, 6, of Fort Worth, Texas, died about 11:30 p.m. Sunday after doctors spent several hours struggling to stabilize his condition.Huddleston was buried for about 45 minutes before he was rescued on the mountain near Crested Butte, Colo., officials said.

The nursing supervisor said she was unsure about the official cause of death.

Authorities said Huddleston and two cousins, Irwin and Michael Effler of Toledo, Ohio, were playing behind a condominium complex in Crested Butte around 11:15 a.m. when a snowmass 300 feet long roared down from a mountain ridge above them.

"The whole ridge came loose," a police spokesman said.

Dozens of rescuers rushed to the site across the street from the Crested Butte Ski Area. The Effler boys were found about 15 minutes later, buried in 2 to 5 feet of snow. It took another 30 minutes to find Huddleston.