Tom Ballard, whose Scottish mother Alison Hargreaves died on K2, was climbing Nanga Parbat in Pakistan with Italian Daniele Nardi when they lost contact a week ago.
A Pakistani official said that two military helicopters will again try to fly four Spanish rescuers to search for the pair on Nanga Parbat today.
Karrar Haidri, secretary of the Alpine Club of Pakistan, said that Spaniard Alex Txikon and three colleagues, including a physician, who are going to try to help find the missing climbers on “Killer Mountain”, will join Pakistani mountaineer Ali Sadpara, who is already at base camp.
Italian ambassador Stefano Pontecorvo tweeted the helicopters had taken off and that he hoped the search would start shortly.
At around 6am UK time, he tweeted: “Army Aviation took off from Skardu at 11.00 to drop @AlexTxikon and the team at Camp-1 #NangaParbat notwithstanding very low clouds/low visibility conditions in valley along the intended route.
“Search for @NardiDaniele and Tom Ballard will be on shortly...”
Mr Ballard was born in Derbyshire, but moved to the Scottish Highlands in 1995.
His mother died on K2 when she was 33, months after becoming the first woman to conquer Everest unaided.
Friends of the climbers have raised more than £104,585 towards the search effort in two days through a GoFundMe page.
The target of the fundraiser is 150,000 euros (£128,500).
A message on the page states: “We are so grateful for everyone who has led these rescue efforts on the ground.
“The helicopter rescue operation costs roughly 50,000 euros (£42,846) per day. Donations to help support these costs are graciously appreciated.
“Any unused donations will be donated to the schools of Pakistan where Daniele has regularly donated school materials and medicine on this and past expeditions.”