Victoria authorities and locals are desperately searching for a mother-of-three who failed to return home after setting out for a 20km run through bushland on Sunday morning.

Ballarat resident Samantha Murphy went missing after going for a run in Canadian State Forest, with police describing her disappearance as out of character.

“Police and family have concerns for her welfare due to the hot weather on Sunday and her disappearance being out of character,” Acting Inspector Lisa McDougall said on Monday.

“Obviously, yesterday [Sunday] was a hot day [36C] … there [is] obviously increased risk there because of the heat.

“It raises the urgency of the search for us and obviously we account for the fact that will have an impact on someone’s health.”

Murphy’s husband said she is an avid runner who is very familiar with the area.

The morning Murphy vanished, she was seen on her own CCTV system wearing a brown singlet and black half-length leggings.

Samantha Murphy is 51 years old and described as tall with blonde hair, last seen wearing a brown singlet.

On Monday, Acting Inspector Lisa MacDougall said Murphy’s mobile phone had pinged Buninyong, a town 11km from Ballarat, but “inquiries are ongoing as to whether [the phone] is still on”.

“Obviously, phones can run out of battery, but that forms part of the investigation.”

Her phone pinged just hours after she vanished and has since gone silent.

Twist that could change search for missing mum Samantha Murphy

In a possible twist that might change the direction and nature of the search, residents living near the forest where Murphy went missing have raised concerns about unnoticeable mine shafts in the area.

One local said mine shafts in the Canadian State Forest were a “major concern”, explaining to A Current Affair: “The mine shafts out there aren’t very noticeable in some areas.”

Crews have scoured dense bushland in the Canadian State Forest for missing woman Samantha Murphy.

Forest Fire Management Victoria, CFA, SES and Victoria Police’s dog squad, mounted branch, solo unit, and air wing are supporting the official search led by police search and rescue.

Paula Heenan, a friend of Murphy, told ABC they’re hopeful of her return but described the situation as surreal.

“We just can’t fathom what might have happened or how it happened, how somebody can just disappear.

“It is just indescribable ... how bizarre it is.”

The Murphys are well-known in the community, with the family owning a car repair business and Samantha being heavily involved in the local theatre scene.

Buninyong and district community president Sue Yorston said the community is hurting in the wake of the beloved mother’s disappearance.

“It’s one of those things you say, ‘not in my backyard’. It’s unusual for a town like Ballarat,” Yorston said.

“It’s a person that’s familiar with doing that sort of exercise and has taken care of herself but obviously something has happened along the way.”

Murphy’s husband was pictured speaking with police on Tuesday, and indicated he wouldn’t be joining the search, instead preferring to stay at home to try keep his mind busy while he awaits updates.

He told the Herald Sun he’s doing “not too bad under the circumstances”.

“It’s just up in the air, we don’t know,” he told the Herald Sun.

“It’s just a whole time thing at the end of the day.”

The search continues.