One adault and one child were killed and three people were injured Monday night, including two children, when a Jeep carrying the group plummeted 300 feet down a ravine off a dirt road near Cazadero, in west Sonoma County.*

The crash occurred sometime around 8 p.m. or earlier on Monday night. CHP's Golden Gate Air Division was on the scene providing medevac support for three injured people, including the two children. And as CHP reported on Facebook, there were "major injuries" to all five individuals and the area where the crash took place made the rescue operation complex.

"Access to the area is difficult as firefighters are using ATVs to access the scene," CHP said.

With Santa Rosa Memorial Hospital fogged over on Monday night, one critical patient was airlifted to John Muir Medical Center in Walnut Creek.

The road where the crash took place has not been reported, but it was in an area northwest of Cazadero, per KTVU. The cause of the crash is not known.

KPIX reported that an approaching fog bank also complicated the rescue operation.

The names of the victims are being withheld pending notification of next of kin.

CHP Santa Rosa is handling the investigation into the crash, and no further details have been revealed as of Tuesday morning. The CHP said as of Monday night that "the scene is chaotic and the investigation has just begun."

Update: The two fatalities were a father and son, identified as 32-year-old Matt Sousa and his son Jason. A 49-year-old man in a second Jeep, who attempted to rescue the first Jeep, was seriously injured when the second Jeep also overturned in the ravine.

Photo via CHP Golden Gate Air Division