HONOLULU (KHON2) — The National Transportation Safety Board released its preliminary report Friday for the ongoing investigation of the air turbulence incident on a Hawaiian Airlines flight from Phoenix to Honolulu.

According to the NTSB, Hawaiian Airlines flight 35 was smooth flying, until the plane reached about 40 minutes out of Honolulu. The report said, the captain saw a cloud shoot up vertically like a smoke plume in front of the plane.

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“This was really a hard piece of turbulence to anticipate, because there was nothing showing on the radar; and at these altitudes, there’s very little moisture,” said Peter Forman, an aviation expert and retired commercial pilot. “So if you’re going to pick something up on radar, it’s the stuff way below you.”

The report states, the cloud shot up in a matter of seconds and there was not enough time to deviate. The captain then called the lead flight attendant to notify her of possible turbulence; but one to three seconds later, the plan experienced turbulence strong enough where some passengers said they were floating off their seats and video shows damage inside of the plane.

The National Weather Services said these types of weather events are rare and they can happen within the blink of an eye.

The report said the NWS did issue a warning for thunderstorm in the area and there were no pilot reports of severe turbulence along the route before the incident.

“Some of these updrafts or upward motions can be 40 mph or more, so nothing can be there; and then in a matter of minutes, you can have a well developed cloud in front of you,” said Derek Wroe, a National Weather Service meteorologist.

The NTSB said, six passengers were seriously injured and 19 sustained minor injuries. The aircraft experienced minor damage.

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Experts said, the best practice is to always leave your seatbelts fastened even if the seatbelt sign is off.