Am I missing something?
"Turbulence" to my memory has never "rolled" the helicopter....pitched up...yawed...perhaps a very small amount of roll....lots of vertical oscillations....but never even remotely close to the roll being described here.
A late response here, Sassy, but in the late 80s I was flying a BK117 in the NSW Blue Mountains, planning to rescue a man from the bottom of a cliff. The wind was very strong from the west, and we would not have attempted the task in the B206, but we felt comfortable in the BK. Until we got into the mechanical turbulence from the cliffs - we rolled to 120 degrees, recovered, and decided to not rescue the man after all. Landed nearby and had a coffee while the ground people collected him. He was an attempted suicide, took pills, stood on the edge of the cliff and shot himself, fell down the cliff but survived. Some weeks later he was more successful.