BANGKOK — A well-known elephant sanctuary in Thailand appealed for help on Friday after torrential flash floods forced the evacuation of about 100 elephants.

Videos and pictures released by Elephant Nature Park near the northern city of Chiang Mai show elephants wading through belly-deep floodwaters, the tips of their noses poking like periscopes out of the murky deluge. Some were accompanied by staff members, the water lapping up as high as their chests.

The sanctuary, also home to injured,…