I am sure the clip is of USAF Hercules. Normally free drop ( i.e no parachutes) goes out at 50 feet, at least in the RAF. If you look at the a/c and it's shadow I think you will find they are low enough especially given the terrain. A lot of dust etc does get generated on those types of DZ. Respect to those crews doing a very difficult job very well. And yes I have the tee shirt !