Belief the use of an emergency mobile alert saved the life of a missing woman, in Christchurch

The alert - after 8.30 last night -advised a 79 year old woman with a medical condition - was missing from Bishopdale.

Using Facebook to coordinate, the community leapt to action and searched local schools, parks, and gardens.

She was found within two hours.

Local councillor Aaron Keown says the community response was incredible.

He says it was unreal to see hundreds of people searching, and posting online to share where had been searched.