Finally got around to watching the video. It was pretty interesting. Except that based on the magnetometer readings of vorticity on the ground, they had their arrows wrong on part of the tornado diagrams (according to the right-hand rule). The ground reading show counter-rotating magnetic field vectors. You only get that if you've got currents flowing in opposite directions (makes sense since currents must flow in a circuit). But their tornado diagrams have both sets of arrows pointing downward toward the earth. Not so based on the field readings... Minor quibble. Otherwise quite interesting.