Poor Ariel! I'm glad you caught it quickly.
Maia had a heat moment earlier this week too. Like her dam, she normally handles high heat & humidity just fine, but for some reason on Tuesday, she was just dripping rivlets sweat. She was still drinking and passing manure, so not in anywhere near the distress of Ariel, but it was still a worrisome moment.
I rigged a second fan for her:

We think she was probably laying down when she became overheated — the existing fan sits on top of the wall, outside the vertical bars, and there was no breeze through the barn aisle that day. If she was laying down, that fan would have passed right over top of her, and not done much good.
No, she cannot reach the cord ... I didn't want REALLY hot horse
