I see here, in that video of impact, a replay of the final seconds of the Hawker airshow crash on a larger scale. More or less as Grumpi described - an attempted pullout from a high-speed dive for which there was simply not enough altitude for successful recovery.
Resulting in a shallow ground contact at very high airspeed, and ejecta from the aircraft (probably, from the flying fireball, the center wing/fuselage section containing fuel) and other debris forward over a large distance.
That, of course, will not be the critical cause, which is **whatever** occurred at or about 6000 feet and caused the steep dive in the first place. Simply the outcome.