Police say missing Sophie Smith left her Gorleston home in Avondale Road without her mobile phone and officers are concerned about her wellbeing.
Local police Insp Will Drummond said police were particularly concerned because of the time she went missing, the fact she left wearing clothing ill-prepared for the weather and her actions before she vanished.
She left home at about 3am on Boxing Day morning wearing just a vest and shorts.
She also left home without her mobile phone.
He added: 'Her family are as concerned as we are. Dedicated officers are working with the family and any new information is going straight to them.'
Sophie is described as being white, about 5ft 8, of a slim build with shoulder length blonde hair. It is believed she was wearing a dark coloured vest top and light coloured shorts.
The Norfolk Lowland Search and Rescue (NorLSAR) have been called out again today to assist in the search effort and police are also continuing their search efforts.
Officers said they would like to hear from anyone who may have seen Sophie or knows of her current whereabouts.
Anyone with information should contact Norfolk Police immediately on 101.
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