Last year, Highland Council turned off turbines at 16 schools amid concerns they may be sited dangerously close to pupils.
But after a comprehensive risk assessment was completed, 13 were turned back on with the remaining three deemed inefficient.
Since then, none have operated in wind speeds over 100mph, even though they are considered safe at 134mph, according to the council.
But on Friday evening, during what is being described as a "not very remarkable gust of wind of around 40mph" a privately owned 25.9 metre wind turbine on Scrabster Hill, near Thurso, was badly damaged
According to local reports the turbine is about 235 yards off the A836, which runs westward from Thurso.
An observer noted that one piece of debris from the blades was thrown "70 paces, say 60 yards" from the turbine.
Lyndsey Ward, a campaigner against wind farms in the Highlands, said: "This is yet another lesson to be learnt from, but experience suggests that it will not be put to good use."
She added Highland Council steadfastly refused to acknowledge any risk from siting small wind turbines in school playgrounds and considered that only at more than twice the wind speed which destroyed the Scrabster Hill turbine was there any need to consider action to close them down.
A Highland Council spokesman said it was concerned to learn of the damage, but was satisfied with the risk assessments it had in place.