Mr Ballard, who grew up in the Highlands, is the son of Alison Hargreaves, who died descending from the summit of K2 in 1995, the same year she became the first woman to conquer Everest unaided.
An intense rescue effort led by Spaniard, Alex Txikon, and experienced Pakistani mountaineer, Ali Sadpara, even deployed drones in an attempt to find the two men, with a powerful telescope also used to scour the ridges.
But with numerous helicopter, foot, and drone searches showing no trace of the pair, it was decided to stand down the operation after several days of poor weather.
Karrar Haidri, the secretary of the Alpine Club of Pakistan, said it had been “a very painful decision” to make.
Mr Ballard, 30, was born in Belper, Derbyshire, but moved to Fort William at a young age. He is regarded as a skilled climber. In 2015, he became the first person to solo climb all six major north faces of the Alps in one winter.
Despite losing his mother when he was aged just six, he shared her love of mountaineering. “Up on the mountain, I feel totally at ease,” he once remarked. “It’s down here that I feel uncomfortable.
“I am regularly asked, ‘What do you think about when you’re climbing a mountain: your mother?’ To which I say, ‘No. Oddly enough I am thinking mainly about not falling off.’”
Mr Nardi, 42, from the Rome area, had attempted the Nanga Parbat summit in winter several times in the past.
The two set out on 22 February, making it to the fourth base camp the following day. They last made contact from an elevation of some 6,300 metres.
Two Pakistani mountaineers had been with the pair initially but decided to turn back because they thought it was too dangerous.
The route Mr Ballard and Mr Nardi were attempting on the peak - known as the ‘killer mountain’ - is called the Mummery Spur.
Before the search was called off, Italian ambassador, Stefano Pontecorvo, tweeted about the operation and shared photos of the snow-covered mountain.
Heavy snowfall over recent days had also raised fears that the climbers might have perished.
Bad weather last week twice forced the search teams to halt the operation but Pakistani military helicopters flew even after Pakistan shut its airspace over an escalation with neighboring India over the disputed Himalayan region of Kashmir.
After the search was called off, adventurer Alastair Humphreys was among those to pay tribute to Mr Ballard and his family.
“My heart goes out to his sister and dad who have now lost both Tom and mum Alison to high-altitude mountaineering,” he wrote on Twitter. “So very sad.”
A crowdfunding campaign set up by friends of Mr Ballard and Mr Nardi has raised more than £120,000 towards the cost of the search and rescue operation, with any unused donations going to schools in Pakistan.