Firefighters near Grande Prairie, Alta., used their specialized training to rescue 10 frantic horses that broke through an ice-covered slough on Sunday.

Dramatic video shows how firefighters saved the horses, three of which later died from the ordeal.

The herd had wandered onto the ice before falling through, said Trevor Grant, regional fire chief in the County of Grande Prairie.

"With the warmer temperatures, the ice on the dugouts the horses are used to being on all winter is a lot thinner," Grant said.

About 35 regional firefighters and members of a search and rescue team responded to the call about 65 kilometres west of Grande Prairie, which came in at around 4:15 p.m.

Firefighters used chainsaws to cut pathways to the shore. They then used slings and boards to get the horses over the mud and melting ice at the edge of the slough.

All 10 horses were removed from the water by 6 p.m., but three died later: two from exhaustion, and one from injuries incurred due to the kicking of other horses, Grant said.

That ice can change in a matter of hours. What was safe in the morning may no longer be safe in the afternoon. - Regional Fire Chief Trevor Grant

A veterinarian said Monday that the seven remaining animals were in good shape and should be OK, Grant added.

"To rescue seven was a great feat, especially when having such a large number in the water," Grant said.

The rescue was especially rewarding for the firefighters from La Glace, as several members are trained in large animal rescue, Grant said. "This program has been evolving over the last couple of years out of the need."

Grant is warning landowners to be aware of their animals around sloughs at this time of year.

"With the changing conditions, that ice can change in a matter of hours. What was safe in the morning may no longer be safe in the afternoon."