According to a report by the Colorado Passenger Tramway Safety Board, problems with the chairlift’s electrical drive/control system “contributed to a rare dynamic event that occurred on the lift at the time of the incident.”

The four-person chair carrying Kelly Huber, 40, and her two young daughters hit a support tower at Ski Granby Ranch about 90 miles west of Denver on Dec. 29, causing the family to fall onto hard-packed snow.

The San Antonio woman died from a ruptured aorta and other traumatic injuries, an autopsy concluded.

Her 12-year-old daughter was treated at a local hospital and released, while her 9-year-old daughter was flown to a hospital in suburban Denver. The younger daughter’s condition has not been released.

The report did not elaborate on the electrical problems, but it concluded that the family, environmental factors and the weather did not play a role in the accident on the high-speed Quick Draw Express lift, which has been operating since late 1999.

A phone call to a representative of the resort was not returned. Tramway safety board spokesman Lee Rasizer declined to comment about the accident until the investigation is completed.

On its Facebook page, Granby Ranch offered condolences to the family and said the resort “places the highest value on the safety of our guests and the safe operation of all lifts and equipment.”

The lift has been closed since the accident, but it is expected to open Jan. 10 under restrictions. The resort has agreed to disconnect the electrical drive and operate the lift using diesel power. It also must increase inspections.

Fatal falls from U.S. ski lifts are rare. The National Ski Areas Association says there have been three deaths since 2004 in falls not related to mechanical problems.

The last fatal fall in Colorado, which accounts for more than a fifth of skier visits nationwide, happened in 2002 when the manager of Winter Park Ski Resort fell about 15 feet from a lift after suffering seizure-like symptoms.

In 1976, four people were killed after cable wires became entangled in a gondola at Vail Mountain Resort.

In 1985, two people died at Keystone Resort after the welding on the large wheel used to pull the cable failed.

(THOMAS PEIPERT)