A rescue team was dispatched because there were victims stranded in the mountains.
The families of the victims are praying for their safety.
遭難者 is used for someone caught in an accident or peril such as being stranded at sea or in the mountains, while 被災者 covers disaster damage more generally.
Compound of 遭難 (そうなん, 'distress, disaster') + 者 (しゃ, 'person').