[James]

Yeah, the high / light definition seems strange to me, because I think of light wind as non-planing conditions.

For me it's like this:
0-10 kts = light wind, usually no planing
10-15 kts = moderate wind, planing on big gear
15+ kts = high wind, planing on small gear

That's for freeride. Maybe for slalom it's different, like 12-20 kts is light and 20+ kts is high.