The Waroo 5m is an amazing storm kite.
I would rate it for 30+ knots to 50+ knots
It's pretty twitchy but very manageable and can get high attitude during
jumps (the Grunt 5m is more stable but can't compare when it comes to
altitude) if you just let it go up before turning it forward for landing.
Another school instructor and I used it yesterday after the lessons and felt very comfortable with it even during the 49.1 knots gust.
P.S., I would love to try out how fast I can go with the 3m Waroo and a
pair of good downhill racing skis in a stormy winter day. Where can you
buy a good pair of classic downhill racing skis these days?
P.P.P.S., Assuming that one can go 1.1 times as fast as the wind on flat
water and 1.5 times on snow, would it mean that we can clock 55 knots on
flat water and 75 knots on snow in 50 knots wind? So far, I don't feel
the 5m nor the 3m Waroo has reached its speed limitation yet (I have
seen the Wipika Classic 3.5m and the Grunt 5m speed limitations).