My guess would also be that they hit a strong updraft causing the airframe to be overstressed. As to why the plane rolled left and not right, there could be several explanations.
-First could be that the left wing broke off slightly before the right wing, starting a rolling motion to the left, which continued as the plane spun in.
-Another possibility is that the right wing broke off first, but that the aircraft was actually in a stalled condition as the wings broke away, causing the heavier left side, with the wing still attached momentarily to drop.
-A third possibility is that the right wing broke off first but that the turbelance surrounding the aircraft overrode the tendency of the left wing to try to rise.
-A fourth possibility is that right wing broke off first, then in that fraction of a second, the pilot feeling the plane entering a right roll, input full left aileron and stomped in some left rudder, trying to counteract the roll, and actually succeeded in stopping the roll just as the other wing broke off. (In Aces High I have had a wing completely shot off, and before I realized that the whole wing was gone, tried to hold the roll using full control inputs. In some planes you can actually stop the roll for about two or three seconds if you are fast enough on the controls, and as long as your airspeed remains high. Nonetheless, I consider this theory as the most unlikely for numerous reasons, for example, I'm not sure if the aircraft has sufficient control authority to counteract total loss of lift on one side of the aircraft, even for a second, especially if the engines on the left wing were still running at full power.)
-The final possibility is that both wings broke off at the same time, and the plane just happened to roll left.
Whatever happened, the fact remains that a brave aircrew died doing a dangerous job. They are heroes and should be remembered as such. My sincere condolences to their friends and families. Salute to air tanker crews and all firefighters everywhere, and a big salute the 3 crew members on this one. May they rest in peace.
