UPDATE: Myrna Burgess has been found safe.
Ground search and rescue, along with helicopter, are searching a vast area from Murchyville Road in the Musquodoboit Valley area to Porters Lake Provincial Park for an 81-year-old woman.
RCMP say Myrna Burgess and a family member, an 83-year-old man, had visited Porters Lake Provincial Park Monday.
"Myrna and a family member set out on Monday for a drive in their vehicle, they encountered some vehicle problems which resulted in them having to sleep overnight in the vehicle," Cpl. Dal Hutchinson told HalifaxToday.ca.
Around noon Tuesday, Hutchinson said the man left Myrna with the car on an unknown road in a wooded area and walked off to get help.
After several hours, he was able to find people willing to assist him, but they weren't able to locate where he left Myrna and the vehicle. They called police just before 1:30 a.m. Wednesday.
The man was taken to hospital and released.
"Right now we're trying to narrow the search area down," said Hutchinson. "The Murchyville Road area is where we have our command post set up and we're starting our search from that area, but we're really pleading with the public for their assistance."
Myrna Burgess is described as white with short white hair. RCMP say she has mobility issues.
The vehicle is a grey 2017 Dodge Caravan with the Nova Scotia licence plate BZF 082.
The 83-year-old man remembers talking to two men on bicycles while walking on Tuesday.
"We would very much appreciate them reaching out to police," Hutchinson said. "They may hold an exact location where they saw this gentleman, which would narrow down the search area."
Anyone with information is asked to contact Musquodoboit Harbour RCMP at 902-889-3311.