If you listen to the highway station FM 98 or 99 you can get up to date information on I-15 the Cajon Pass. I work in Anaheim and leave at around 5AM. They report on the traffic quite often and is very reliable.
If you have a flight scheduled, I would contact the airline asap and let them know the problem so they can reschedule it for you. Do not no-show your flight. If you do the ticket usually becomes non-refundable.