State investigators blamed a fatal ski lift accident last December on two factors – the recent modification to an electrical drive and control system on the Quick Draw Express and repeated speed changes “immediately prior” to the moment a Texas woman was thrown to her death, according to the final report obtained Thursday by KENS 5 sister station 9NEWS in Denver, Colorado.

The woman’s two daughters were also hurled from the lift and injured in the Dec. 29 incident.

The report by the Colorado Passenger Tramway Safety Board suggested that an unidentified operator altered the lift’s speed. That determination was based, in part, on statements from multiple witnesses and information collected by a device on the lift known as a “data logger.”

“According to the operator, he did not remember making any speed change prior to the incident,” the report said, in part. “Although the data logger does not record speed changes, there is supporting evidence indicating that rapid and significant accelerations/decelerations of the lift occurred immediately prior to the incident.”

RELATED: San Antonio mother killed in ski lift accident identified

Kelly Huber, 40, of San Antonio, Texas, died after falling approximately 25 feet onto hard-packed snow, and her two daughters, ages 9 and 12, were also thrown out of the chair and injured.

A Ski Granby Ranch official could not immediately be reached for comment.

A decision about any disciplinary action that could be taken by the state is pending.

The report noted that data captured by the lift showed that at the time of the accident the lift was accelerated into the “fast” position – the Quick Draw Express’s maximum licensed design speed – and that evidence indicated “that the operator had not allowed the QDE lift to reach its steady state speed before commanding a Fast.”

At the same time, the modifications to the electrical control drive, the investigation found, “may have resulted in the drive trying to respond too aggressively to lift demands when changing from ‘Fast’ to ‘Slow’ and back to ‘Fast’ again.”

The operator of Ski Granby Ranch had suggested back in January that a contactors modifications to the electrical drive and control system of the Quick Draw Express led to the tragedy.

The malfunction sent the chair carrying Huber and her daughters into a support pole, throwing them to the ground.

At the time, Ski Granby Ranch CEO Melissa Cipriani said the lift had operated safely for 16 years – “up until an independent contractor made modifications to the lift’s electrical drive/control system before the start of the current ski season.”

Following those unspecified modifications, the lift was tested on Dec. 5 and licensed by the state on Dec. 9.

It was put into operation on Dec. 16.

Thirteen days later, Huber died and her daughters were injured.

The lift was closed while state regulators investigated. The Colorado Passenger Tramway Safety Board allowed it to reopen on Jan. 10 but required that it be operated by a diesel engine rather than the electrical unit that is believed to have malfunctioned.

The ski area later shut it down again after it experienced “unusual/irregular conditions.”

The report made public Thursday came months after Investigators had concluded “that environmental factors, weather, and the occupants of Chair No. 58 did not contribute to the cause of the incident.”

Huber suffered a traumatic rupture of her aorta, the main artery leading away from the heart, according to an autopsy. She also suffered other blunt force injuries.

Fatal lift accidents are rare – before this incident, the last occurred in 2002.

Contact 9NEWS reporter Kevin Vaughan with tips about this or any story: or 303-871-1862.