Yes, very dangerous! Spring loads, twist loads, teeters, hangers, trip hazards, unstable root wads, ect. and it can be difficult to see them all. One must be paying close attention and pick it apart like a puzzle. Piece by piece step by step. I've had more close calls cut'n windfall patches than I ever have cut'n standing timber. I've had my saw jerked out of by hands and thrown thirty feet away from me, had the pistol grip shot into both my chest and my face, I've been catapulted in the air over ten foot high. The list goes on and I have an extensive amount of experience dealing with wind fall. Storm damage is not to be taken lightly by any means.
The bottom line is. I really frick'n don't like dealing with it. This particular patch wasn't too bad thankfully.