The 28-foot recreational boat, Over the Moon, overturned on June 21 near D.L. Bliss State Park.
The National Transportation Safety Board (NTSB), which is leading the investigation, said the boat was caught in a sudden and severe weather change while trying to return to a marina.
According to investigators, the boat had left Tahoe City that morning with four people on board. Six more adults joined later at a nearby marina. The group spent about an hour anchored at Emerald Bay.
Skies were clear earlier in the day, but by mid-afternoon, storm conditions developed quickly.
One survivor told officials that waves up to 10 feet high crashed into the boat as hail and snow began to fall. The boat’s engine eventually stopped, and it was hit by a large wave, flipping it over.
A group of hikers witnessed the boat capsize. At 2:58 p.m., one of the hikers called 911. Another hiker and a California State Parks lifeguard helped recover the survivors from the water. Multiple agencies responded.
The snow stopped at around 4 p.m., and the weather began to clear.
Six people were found dead that day. The other two were recovered from the lake the next morning. Of the two survivors, one was wearing a life jacket and the other was clinging to one. They were both taken to a hospital for medical treatment.
Investigators said there was no sign the boat hit anything, and no spilled fuel was reported.
Several life jackets were found still in their original packaging. The boat had been built in 2023 and was valued at nearly $393,000.
Toxicology results for the victims are pending.
