..could it be that the pilot had decided the wx was too bad, he knew where he were, that The Sheriff's Agoura Rd. HeliPad was close, and due to the bad visibility he turned a few seconds too early, thinking he just had to cross Agoura Rd. and then he would be at the HeliPad - then realising that he turned the wrong place, and due to limited visuals he was ending up in a non-normal which he couldn't get out of..? It only takes a few seconds to lose control due to vertigo and such, close to ground.