Environment Canada says much of the hail was the size of golf balls and loonies, but an area 13 kilometres southeast of Weyburn saw ice chunks the size of grapefruits.
"With a grapefruit we're talking about nine centimetres in diameter," said meteorologist Mark Gerlyand. "Very humongous."
Gerlyand said the town of Oxbow received 50 millimetres of rain in just 15 minutes.
There are also unconfirmed reports of a tornado near Minton.
Gerlyand said Environment Canada has not received any photos or videos that would allow them to confirm it.