The small Jack Russell, named Vivienne, alerted Helen and Geoff Packer when their smoke alarms failed to go off after their house on Glen Avenue in Unley Park caught fire around 3 a.m.

Helen and Geoff, both part of a well-known Adelaide business family and grandparents to Connor Rozee’s wife, Maisie Packer, were reportedly asleep when the incident occurred.

According to the Metropolitan Fire Service (MFS), the home’s fire alarms did not activate due to the external nature of the fire’s origin. 

It started in the carport before rapidly spreading to the home’s roof.

The couple’s house was extensively damaged by fire, with the estimated cost of damages reaching $2 million dollars.

“It’s a pretty bad day for them, they’ve lost most of their house. However, the Jack Russell dog has woken them up and they’re unscathed,” MFS’ Gideon Douglas said.

“Hundred per cent that dog needs some treats today,” he said.

Neighbour Scott Fox tried to contain the fire with a garden house before firefighters were on scene. 

“I thought if I could get some water on the exterior of the building it might not be able to catch it but it was raging, it was pretty hot,” Fox said.

The Packers, who have resided at the property for three decades, are insured, but are unsure about rebuilding due to their ages.