A hot air balloon went prematurely airborne with a tour company representative clinging to the basket's rim, severely injuring the woman when her grip finally slipped at a height of 10 meters.
Saturday's incident, at a strawberry festival in Lääne County, occurred while three passengers were already in the gondola.
The woman's job was to make sure the aircraft stayed balanced while in the air, ETV reported.
A gust of wind is thought to have knocked the balloon from its moorings. The woman was taken to hospital in the county seat of Haapsalu, where she is listed in stable condition.