Mrs Hall (48) was driving home when her car ran off the road and crashed into a macrocarpa hedge.
Adam Hall, accompanied by Mrs Hall, his father Lindsay and sister Mikaeyla, received a hero's welcome at the airport last week when the family returned home with the gold medal Adam won in the men's standing slalom at the Winter Paralympics in Whistler, Canada.
Mrs Hall, a midwife, was on Otokia Rd West, south of the airport, when her vehicle ran off a straight section of sealed road and crashed into the hedge about 8am.
The car's only occupant, she was trapped by the impact and had to be extricated by the fire service.
Police are still investigating the cause of the crash.
It is understood husband Lindsay was the first person on the scene.
Adam Hall was told of his mother's death by police officers at the TVNZ studio, where he was to appear on the Good Morning show.
He flew back to Dunedin as soon as possible, arriving late yesterday afternoon.
Family spokesman Kevin Davidson, a family friend who is also a sergeant with the Dunedin police, said the family was still reeling from the sudden loss of a loved mother and wife.
They were trying to cope with Mrs Hall's death and would make a statement at a later date.
They asked media to respect their privacy in the meantime, he said.
Friends and colleagues who had shared in the family's joy, were yesterday trying to come to terms with the death of a much-loved woman, described as the "rock" of the Hall family.
Kereyn Smith, chief executive of the New Zealand Academy of Sport South Island, said Mrs Hall was "the absolute rock and driver for the family.
She had energy and vitality and played an important part in Adam's programmes and plans".
"Our hearts go out to the family and to Adam because his mother was always there to support him. It is a sad day and it will be a difficult time for the family."
New Zealand Academy of Sport winter performance programme director Ashley Light was saddened by the news.
"Everyone in the winter sports industry is obviously desperately saddened by the tragic news," he said.
"She was an inspirational lady who served not only her family but the community at large as a midwife and was an active person in the disabled community."
Dunedin Mayor Peter Chin said Mrs Hall's death was devastating.
"They were in the midst of celebrating huge success, and rightly so, and now they are really in the depths of despair."
He said he wished to express his deepest sympathy, on behalf of all Dunedin residents, to all of the Hall family.
Colleagues of Mrs Hall, who was a midwife at Queen Mary Maternity Centre at Dunedin Hospital, were grief-stricken at the news, friend and long-time colleague Kerry Adams said.
Mrs Hall was a "larger-than-life" personality who had an amazing sense of humour and was loved by everyone.
"She had an incredible passion for midwifery and she absolutely adored her children," she said.
Mrs Hall's colleagues had lived Adam's whole journey to the paralympics.
"It was her dream that he would win a gold medal and she got to live her dream. We are all just so pleased she got to see that."
