[RWebb]

Elon Musk says the Model S struck a "large metal object" as it traveled at highway speeds. It went under the car and struck with a force "on the order of 25 tons." He says the estimate is based on the result: a 3-inch hole through armor plate that compromised the car's battery pack.

But from there, he says everything went as it should. The car's "onboard alert system" directed to the driver to stop and get out. The fire was contained by firewalls within the battery pack. Vents in the pack directed the flames down and away from the vehicle.

The fire department followed the correct procedure in trying to deal with the fire by puncturing holes in a protective plate and shooting water into the pack.