The overnight temperature in the area at an altitude of over 1576m was around freezing, said Commander Lin Cheng-I of the Nantou County Fire Department.
In a message to be passed on to the Nantou fire service, Wu revealed she had stumbled more than 19m into a narrow gorge while trying to ascend Taiwan's highest peak.
Wu has a large social media following because of her bikini adventures.
In 2018, she revealed she spent 127 days - roughly a third of the year - hiking.
On Christmas Eve, she also shared an image showing her bruised legs after another fall, which she admitted she was lucky to survive.
Many of her Facebook friends have left messages of condolences after learning of her death.