I was driving to work. I was southbound(ish) on Imperial Hwy (right where it changes to Cannon) near the intersection of Via Escola and Imperial in on the Anaheim/Orange border. Just past the intersection, I noticed a ball of fire traveling from the east, in a straight path, descending at a 15-20 degree angle and toward the open space. It traveled under the cloud cover. My first thought is that a small plane was crashing. The shape, however, was more like a sparkler; a burst of fire toward the front and a small black tail toward the back. Just prior to the ball of light hitting the hill off to my left (this is the hard part to describe) the sky opened up and the ball of fire went "poof" into the hole. The ball of fire and the tail were gone. The entire episode was around 10 seconds.I entertained the idea that kids were shooting off fireworks. I ruled this out. A sparkler fired into the air would have traveled on an arc. The path of this fire ball was straight.My windshield was clean. I was wearing my glasses. This is my usual path to work over the last 10 years. I have not seen anyting like this in that area before.