(CNN) Rescuers are searching for two mountain climbers missing on a peak in Pakistan, including a British man whose mother died in the same region in 1995.

Mountaineers Tom Ballard and Daniele Nardi have been missing for over a week, after contact was lost with them during an ascent of Nanga Parbat, in the Himalayas.

According to a statement published on Nardi's Facebook page , "traces of (an) avalanche" were seen by rescuers near the pair's base camp during a helicopter flyover last week.

Italy's Ambassador to Pakistan, Stefano Pontecorvo, said on Twitter that efforts had resumed Tuesday. "Plan is to reach Camp 3 and search the surroundings also with the help of the drones."

Search ops for 🇮🇹 @NardiDaniele and 🇬🇧 Tom Ballard under way this morning. Search party @AlexTxikon, Ali Sadpara, Felix Criado, Ramat Ullah Baig. Grateful to have such impressive guys on the job. Plan is to reach Camp 3 and search the surroundings also with the help of the drones pic.twitter.com/6zfIA32PSx — Stefano Pontecorvo (@pontecorvoste) March 5, 2019

While the pair have not been heard from for over a week, both Nardi and Ballard are highly experienced mountain climbers, and are skilled at navigating hostile conditions with limited oxygen.

On GoFundMe , an appeal started by supporters has raised almost $150,000 to assist the rescue effort.

"The helicopter rescue operation costs roughly €50,000 per day," organizers wrote on the fundraising website. "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."

Pakistan Army helis on March 4 flew up to 7,100 metres (23,300 feet) on Nanga Parbat to find missing climbers Daniele Nardi (Italy) & Tom Ballard (UK) - a team of climbers is now searching for them on foot - they were last heard from Feb 24 while trying to attempt a winter summit pic.twitter.com/UyiS4Tojv6 — omar r quraishi (@omar_quraishi) March 5, 2019

Adding to the potential tragedy, according to the BBC , Ballard is the son of British climber Alison Hargreaves, the first woman to conquer Everest unaided in 1995. Hargreaves died that same year during a descent of K2.