My local San Diego affiliate, 10news is running with the TMZ backed story. Haven't seen NY Times or better sources confirm, yet. The fog in Malibu/Hidden Hills/Calabasas cane be heavy and intense, and come up from seemingly nowhere, I have seen it myself in Malibu, a storm rolled in within less than 5 minutes, lightning and thunder, heavy fog, it was like a horror movie. Apparently, he used the helicopter extensively to travel between Newport Beach and LA, and was on his way or coming from when this happened.