A plane that crashed Oct. 7 near White Pass, killing 10 people with Harvey Field-based Skydive Snohomish, ran into clouds and rainy weather over the Cascade mountains, according a preliminary report on the accident.

Released on Wednesday, the accident report does not identify a cause for the accident that destroyed the Cessna 208B Grand Caravan.

It was the deadliest airplane crash in the country so far this year.

“It’s preliminary, factual information about what we know about the accident at this time,” said Keith Holloway, a spokesman for the National Transportation Safety Board. “We will update that and put out more factual information as the accident investigation continues.”

A final report likely won’t be released for more than a year, Holloway said. It’s possible the cause of the accident may never be known.

The Federal Aviation Administration, a partner in the NTSB investigation, found that pilot Phil Kibler may not have received an updated weather briefing before the flight.

While he did not call for a briefing, Kibler could have received one by listening to a broadcast of the weather forecast or by logging onto a weather site before leaving, officials said.

The report found that conditions were clear at the closest weather station in Yakima, but that witness accounts at the accident sites showed that rainy overcast weather was present. The plane was about 50 miles west of Yakima when it crashed.

The plane, carrying members of the skydiving club, left Star, Idaho, near Boise, on its way to Shelton, in Mason County. It was ferrying sky divers between Idaho and Washington after a weekend of jumping with other sky diving groups.

The night of the crash a hunter saw an airplane, heard its engine struggle and then heard a thud, the NTSB report states.

“He noted that the cloud bases were below the mountaintops with misty rain conditions and low visibility,” the NTSB report said.

The report also found that the pilot did not file a flight plan, something officials say is optional.

The last seconds of the flight are also detailed in the report.

The plane, flying at about 14,400 feet, made a tight 360-degree turn, and then lost 1,400 feet of altitude over the next 12 seconds, according to radar data, the National Transportation Safety Board said Friday.

There appeared to be a moment of respite before the plane fell from the sky.

“The aircraft appeared to recover and stayed at (an altitude of) 13,000 feet for three radar hits before it entered a rapid descent of 6,800 feet per minute to the last radar hit at 8,900 feet,” the NTSB said.

The agency used radar “ping” data collected every six seconds to track the flight until just before it crashed at 4,300 feet in the Cascade range near White Pass. Earlier, investigators estimated the plane was going about 70 mph when it nosed into the ground.

The plane was broken into pieces at a site 100 feet long and 60 feet wide, the report found. Several pieces of the plane were buried as deep as five feet in the ground and there was a small impact crater where the plane hit.