Once upon a time, when I was a young and inexpereienced ATR F/O, I was scheduled to make a 120 mile trip to airport that had 25G40, twenty degrees off runway centerline. Bad news was that the airport was on the leeward side of the 5000ft mountain, some 15 Nm downwind of it and that forecasted wind at FL 100 was 80kt, same direction as near the ground. My captain took a look at WX brief and decided to cancel the flight and I agreed that our pax would be much safer and comfortable on a bus. Now ops and dispatch wanted us to wait for a while to see if the winds abates. We couldn't see that happening anytime soon but agreed to wait. While we were waiting, VP flt ops called us, ordered us to make the flight and also made some oblique threats regarding our employment. So we went out to the aircraft.
Plan was now to fly at level till we were overhead destination and descend in holding pattern using turbulence speed. As we descended it was apparently working, we only encountered light chop till we got to FL130 and the wind suddenly stopped. Wind arrow on EHSI made one full circle ant then I couldn't see it anymore as entire instument panel seemed as if it were having an epileptic fit. Not to mention that the occasional manual flying randomly through cockpit, trying to mimic the flight of the giant moth also made instruments reading difficult. Capt was wrestling with the controls while I was trying to set MCT and only succedeed in finding the power and condition levers on the fourth attempt. The whole trashing lasted about half a minute, we've lost about 3000ft and decided to return home and never, ever, repeat the experience again.
I believe that the lenghty report that we co-wrote was carefully buried.