Every time I've seen planes take off from or land at LAX, and when I've flown in and out of there myself (and I've lived here many years), they would approach from the east and take off toward the west. Planes arriving from the west would fly over LA, bank over downtown, and land going east-to-west.
Today, I was driving north on the 405 and was shocked to see planes taking off toward the east, and I could see the lights of low-flying planes over the ocean, approaching to land from the west.
So why was LAX traffic reversed today?
It was mid-morning that I first noticed it, and also later in the afternoon. There were some low clouds in the morning, but no rain, and no wind to speak of. Nor Space Shuttles.
I found this link
but it doesn't explain much except to say that it is indeed rare.