This was VRS. Those saying the decent rate doesn't match VRS I'm sure would have a different opinion from inside the helicopter at the time. He didn't have much altitude to build up a descent rate, but it was more than enough to smash the aircraft to pieces. That counts as "high rate of descent" for me.
Practicing VRS recovery (at a safe altitude) is simple, reliable, and eye opening for those who think it only happens if the wind is a certain way or expect there to be some noticeable feeling in the aircraft.
1. At a safe altitude (say 2,000') fly level at roughly max endurance with power also roughly at max endurance. (It doesn't matter which way the wind is blowing, and you're not maneuvering in relation to ground references.)
2. Without changing anything else, pitch up about 5-8 degrees.
3. Simply hold that attitude as airspeed bleeds off. Don't change power.
4. Altitude might increase briefly, but then decrease. Hold the "wings" level, nose slightly up attitude, and moderate power setting. As airspeed bleeds off the rate of descent increases until you recover with a change of attitude (with decent rate above 300'/min you can also notice the ineffectiveness of adding power).
5. You won't "feel" it (unless you're too low and have ground rush) and the aircraft doesn't feel out of sorts, despite the alarming behavior of the altimeter and VSI. This is important to know for those who think they'll get some kind of seat-of-the-pants warning before VRS.
6. Recover (pitch down or bank/roll).
Fly safe (i.e. paranoid)