Obviously if you were to taxi with full flap and the Vs at that flap setting is say 59kt, then a 59kt head-on wind will lift you off.
But what about ground effect? Does that apply if the aircraft is stationary or near-stationary relative to the ground? If that operated, the wind required to lift you off would be lower.
Then there is wind from the other directions. I have not seen a max taxi wind figure in my POH.
How do people determine this?
High wings – you need to be careful, low wings – not so much. FWIW some airlines have a max wind of 55 kt for anything, including opening a door, because of the risk of stuff being blown into the aircraft.
I keep the tailwheel in the hangar if surface winds are gusting over 20 knots, and would treat 30 knots as a sensible limit for a heavier single engine.
While you can taxi and fly in winds above this, the risk doesn’t seem worth it.
Unfortunately 20 knot winds are not uncommon here and to not fly in a 20 knot wind would really cut into our flying days, but that’s about our limit. You have to be aware of the direction and position the controls correctly all the time. Quartering tailwinds are the worst to deal with. Also turning onto a crosswind taxiway when the only steering you have is differential braking can become challenging.
Does the wind need to be at least Vs to flip over an aircraft if the wind is blowing sideways?
I would say that there is a large arm if the wind “gets under” the wing.
I use a max wind limit of 30kts. Above that it’s no fun to fly anyway 
Taxiing will become problematic with directional control. Taxiing into wind is fine, but as soon as you need to start to turn, the weathercocking effect will be severe in very strong winds. I.e. you’ll need differential braking and full rudder deflection to maintain straight / taxiway centreline. Or for example a turn to backttrack, or line up…
Average light single, probably 15-20 kts upwards will cause some issues.
Peter wrote:
Does that apply if the aircraft is stationary or near-stationary relative to the ground? If that operated, the wind required to lift you off would be lower.
In a tailwheel there are a couple of tactics which might assist.
Sometimes turning downwind is easier going with the wind and in effect carrying out a 270 degree turn, but eventually taxying in a crosswind, and especially a quartering crosswind, is heavy on the downwind side brakes.
If the taxiway has camber, by placing the tailwheel on the upwind side of the camber it will help with controlling the weather vaning tendency.
You need a lot of patience as your taxying speed has to be extra slow – at a big airport you may have to stop to rest the brakes!
I would guess it doesn’t make a difference whether the ground moves at 0 kt, or whether the ground moves at -59 kt. I.e. ground speed has no effect on ground effect.
I agree. So one would need a head-on wind substantially below Vs2 (etc) to lift the plane off.
At Vs you would also need a high angle of attack to produce the lift necessary. Which wouldn’t be the case for a tricycle aircraft.
Actually the AoA is probably similar to the one in cruise, so the wind would need to be a lot closer to your cruise speed in the configuration than the stall speed. I don’t believe that ground-effect would change that significantly.
Easy to test: take-off with no back-pressure on the yoke, see at what speed that is actually achieved at lift-off (assuming a flat runway)
A small boast about my record which was a very genuine 50 knots gusting 55 in a DA42. I recall the taxi turning cross wind was interesting. I also recall aborting the landing at the home base very early on (why did I even have a look), electing to divert where it was almost staight down the runway which fortunately I had considered before because there was almost no where with a suitable runway heading. The only other aircraft flying was a Warrior which was clearly having fun and I think almost managed stationery in the over head.
As so often the case with a northerly it was unpleasantly turbulent and the flight was also memorable because I recall so well just how hard I hit my head on the canopy – there is a lot to be said for proper four point harnesses. Even the CATS into Gatwick were working hard that day!
I could tell a story about my Husky flying skils on a somewhat less windy day but that was mildly embarassing, and as others have said your and their assessment when it comes to high wing is exactly right!
