A woman killed by a falling tree in the NSW Blue Mountains was a senior off-duty paramedic.

Dearne Fulcher, 50, was found dead by emergency services after the tree crushed a Volvo sedan she was a passenger in on Victoria Street in Katoomba just after 7pm yesterday.

Ms Fulcher’s 20-year-old son Dylan was behind the wheel and was rushed to hospital with head and chest injuries.

Dearne Fulcher was killed when a tree crushed a car being driven by her son. (Supplied)

Ms Fulcher was killed and her son was seriously injured in the accident. (9News)

He remains at Westmead Hospital in a serious condition.

“I heard a big bang like an explosion – It was unlike anything I had ever heard in my life,” witness Samantha Jones told Today.

“I came running outside because the power went out and I saw the accident.

“The gentleman who was driving the car, his foot must have got stuck on the accelerator because the tyre was just burning out.”

Dearne Fulcher was a senior paramedic. (Supplied)

Ms Fulcher's colleagues were among those who tried to save her life. (9News)

NSW Ambulance Commissioner Dominic Morgan said the community was struggling at the beloved paramedic’s death.

He said Ms Fulcher’s co-workers were among those who worked to free her from the crushed car.

“It’s a very sad day for the NSW Ambulance family,” he said.

“You can imagine the loss of one of your own has a profound impact on paramedics that Dearne worked with.

“We had the privilege of catching up with some of them last night and I’m just so proud of every person who went to her aid in her greatest hour of need.

“It takes incredible professionals to care for someone they love in the most dire of circumstances but rise to the occasion and do everything they can to save someone’s life.”

Colleagues remembered Ms Fulcher, who was awarded a bravery award for her efforts during the Blue Mountains bushfires in 2002, as a “legend” today.

Mr Morgan said he was among those who had worked with the senior paramedic over her career.

“I remember her to be this commensurate professional who had the ability to touch patient’s lives in a way that was really quite unique,” he said.

Dearne Fulcher was awarded a bravery award for her efforts in the 2002 Blue Mountains fires. (Supplied)

'Legend': Dearne Fulcher was a long-serving paramedic. (Supplied)

The freak accident came amid fierce storms hitting NSW, with at least 127 calls so far to State Emergency Services in the past 24 hours.

The storms also left almost 4000 homes without power across the state.

Winds of 90km/h are expected in NSW today with Sydney expected to see similar wind speeds tomorrow and top temperatures of just 16 degrees.

These stark weather conditions have also seen a solid amount of snow in the NSW ski fields with 27 centimetres dumped in that past 24 hours.