In reply to Flinticus:
We were once on the Drumochter hills (A'Mharconaich) on a day when the wind was measured gusting 150mph on Cairngorm. I guess we got 100ish gusts, being 1000ft lower, during which we could only lie down with our limbs flapping around in the wind. As we were on a nice rounded ridge not too far from the road we crawled, literally, to the summit, rather than turn and run. A memorable experience. I'll never forget the 5 mins it took me to refit a strapped on crampon, whilst lying down, unable to stop my legs from blowing around for long enough to get the straps done up. I would guess it was constant 60 mph+, based on that SAIS clip, with gusts which just knocked us flat.
50 mph has you staggering about a bit. Its easier if constant than if gusting, but its never truly constant enough to 100% commit your full energy to pushing against it.