GRANBY, Colo. – Investigators were trying to determine Friday how a Texas woman fell to her death from a chairlift at a small Colorado ski resort, the first fatal fall in the state in over a decade.

The woman’s two daughters were also injured after falling about 20 feet with her Thursday at Ski Granby Ranch about 90 miles west of Denver. Police identified the woman Friday as Kelly Huber, 40, of San Antonio.

Her 12-year-old daughter was treated and released from the local hospital, but her 9-year-old sister was airlifted to Children’s Hospital in suburban Denver. The Quick Draw Express lift, which brings skiers to beginner and intermediate terrain, will remain closed until state regulators can determine that it is safe for the public to use, said Lee Rasizer, a spokesman for the Colorado Passenger Tramway Safety Board.

Chairlift deaths are rare, both in Colorado and across the country. People are five times more likely to die in an elevator accident and eight times more likely to die in a car accident than on a ski lift, said Chris Linsmayer, a spokesman for Colorado Ski Country USA, the trade group representing most of the state’s ski resorts.

“These things don’t happen very often,” he said, referring to statistics from the National Ski Areas Association regarding deaths due to mechanical problems with chairlifts.