When American mountaineer and guide Don Wargowsky was asked to lead an international expedition of climbers on Mera Peak and Baruntse in November 2018, he knew he'd be leaving his beloved dog - and his fiancée, of course - behind at home. What he didn't expect, however, was that he'd be summiting Baruntse with a Nepalese canine companion by his side, in what is believed to be the first ascent of a 7,000m peak by a dog.

While descending from Mera Peak, Wargowsky was struck by an unusual sight: a 45lb Tibetan Mastiff/Himalayan Sheepdog mongrel dodging crevasses and heading up a glacier towards his team. The dog was familiar to Wargowsky; he had met her in the village of Khare, 2 miles and 2000ft below the glacier, where she had shied away from contact. A few strips of beef jerky later, Wargowsky had found a firm - and furry - friend.

'I instantly begin to picture this dog joining us for the duration of the trip,' he later wrote in a blog about his encounter. 'It would be so great to have a companion, a temporary Nepali therapy dog. Then I start to think about exactly what we'll be doing in the next few weeks and the dream fades; days and days of hiking, then ascending thousands of meters of rope, camping in -30 degree wind chill. If she came with us, she'd surely die.'

But the dog insisted on following the team, seemingly unfazed by the altitude and harsh weather conditions. 4 days and 14 miles later, at Baruntse Base Camp, she refused to sleep in Wargowsky's tent, instead waking up covered in snow after a cold night outside. The next evening, she accepted the offer of a warmer bed and settled in the tent. 'Not everyone is kind to dogs in Nepal,' Wargowsky wrote on earning her trust. 'Many dogs carry rabies and it's common for initial reactions to be negative and sometimes physical.'

At Base Camp, the stray dog was named Mera, after the peak where they met. Now a fully-fledged member of the expedition, Mera was earning her own portion of the leftover food to keep up her energy for the climb. Despite her enthusiasm, Wargowsky remained sceptical about Mera's potential to follow the team higher. 'I assumed she would walk with [the Sherpa] up the dirt and rock trail to where it met the ice and steep rock and turn around,' he wrote. Instead, Mera continued to follow them as they fixed lines all the way up to Camp 1, where she had refused to descend with the Sherpa due to an exposed ravine spooking her.

'I hated knowing that she was alone, exposed to the elements at over 20,000',' Wargowsky wrote. 'It broke my heart thinking of her lying in the snow'. He could do nothing but pray that she survive her exposed bivi. The following day, Wargowsky gave the Sherpa some meat to feed to Mera. '"Give this to Mera is she's still up there." I can't bring myself to say "if she's alive,"' he wrote.

"Dog is at Camp 1! Dog is good!"

Jangbu, the team's lead Sherpa, announced over the radio that Mera was still alive. In the following days, she reached 6,800m with the Sherpa as they continued to fix lines, before descending to reunite with Wargowsky. 'Seeing her again brings a tear to my eye. She has obviously lost some weight and has some minor cuts on one of her feet, but for a dog that just spent five days above 20,000 in the Himalayas, she looks pretty amazing,' Wargowsky wrote. She immediately curls up on my coat and passes out. She's exhausted, and rightfully so.'

Taking Mera back up to her highpoint and to the summit with the climbing team seemed unfair after the previous few days of exertion. The group tied her to a boulder at Base Camp, where other team members would care for her. 'The local staff's attitude toward her has changed from a vaguely tolerant to pure reverence since she returned from the upper mountain. No one has seen a dog like this before. They call her "lucky" and "blessed,' Wargowsky explained. Mera whined as they walked up the mountain and into the distance.

Not content with remaining at Base Camp, Mera somehow became unleashed and caught up with the team half an hour later. A tickle on the back of his knee alerted Wargowsky to her presence. Unable to leave his clients, he settled on taking her with him. The growing bond between the pair became evident as Wargowsky realised her preference to be beside him, rather than taking the easier route for a four-legged creature. 'I couldn't fathom why she was trying the climb this terribly steep snow when she could be on the ridge of rock just a few yards to our left, and then it dawned on me,' he wrote. 'She's trying to stay close to me. If I'm on the snow, that's where she's going to be too. At times choosing the harder route for himself to make things easier for Mera, Wargowsky ascended with the dog hot on his heels, cutting snow steps and becoming a 'safety net' for her when she slid down a slope.

'I watched one paw slip, then another, and the next thing I knew she was sliding down the gully,' he wrote. 'From here, it would be several hundred feet of sliding and cartwheeling until the top of the rock band where she would free fall another hundred feet or so onto the glacier below. Luckily, I am directly below her and I was able to catch her as she slides past me.'

At Camp 2, the team waited for four days for 40-60 mile an hour winds to pass. After two days, some clients chose to descend and give up on their goal. Mera followed them to Camp 1 before returning to Camp 2 in fierce winds. Wargowsky had hoped she'd follow them to Base Camp, but once again the resilient little dog had exceeded his expectations.

'I have limited amounts of food, but I split all my meals with her 50/50,' he wrote. 'She never begs for food or whines, not even when one particularly bad gust of wind rips out all our tent's anchors and moves the entire tent three feet with us in it. Considering we have been trapped in a tent ninety five percent of the time for days on end, she is an angel. I couldn't ask for a better tent mate.'

With the summit in sight, the remaining team began their final ascent. Wargowsky didn't want Mera to follow on the steepest, coldest sections of the climb. She was fast asleep in the tent and they would return to her later. Or so they thought...

While resting after a particularly tough section, Wargowsky turned around to photograph the ridge he had just climbed. 'I see a black ball of fur following our tracks in the snow,' he wrote. 'It's Mera! We've been climbing for seven hours and she's almost caught up with us.'

But the summit was, of course, only the halfway point of the climb. Mera's paws were starting to spot with blood, and Wargowsky knew the descent could be more challenging for a dog. Jangbu constructed a makeshift harness and sent Mera flying towards Wargowsky using a 'flying fox' method of travelling down a steep section along a fixed line. 'When he sees that I'm ready for Mera, Jangbu gives her a nudge over the edge and suddenly she's half falling, half running down the slope,' he wrote. 'She comes flying down the hill and straight into my arms. Everyone yells and cheers for her, but no one more than Jangbu who is pumping his fists in the air on top of the cliff.'

After some tricky leaps and heart-in-mouth moments, the team faced a final hurdle: a 50m abseil. Wargowsky created a harness for Mera, and she patiently descended while dangling below him. Now all that remained was a long walk to town. The inevitable question weighed heavy on his mind: what will happen to Mera when he leaves for the US? 'How could I bring this mountain climbing machine to live in my 700 square foot condo in Seattle? She would hate it,' he concluded. Fortunately, the dog was adopted by Nir Kaji Tamang, the team's base camp manager.

"She will not be left on the street! This is a special dog," Kaji reassured Wargowsky on the descent. "She is lucky and brings good luck to us. She will come to my home and I will feed her good meat at every meal. She will live with me and we will call her Baru, after the mountain that she climbed."

Wargowsky is a self-confessed dog lover. That Baru should find and follow him was serendipitous, but also comforting to him in a spiritual sense. 'Part of me wonders if some of my climbing friends who have gone on to that big mountain in the sky weren't giving Baru a little nudge up the hill for me,' he wrote in his blog. 'Whatever her reasons were, I will be forever grateful for the time that I got to spend with her, and for Kaji for taking care of Baru, the world's greatest mountain dog.'

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Wargowsky has since received several updates from Kaji. Baru is doing well in Kathmandu. 'She gets monthly checkups from the vet and is treated very well. Kaji sent me pictures for Christmas of him and Baru,' he told UKC. Will Baru go climbing again?

'I don't believe that Kaji has plans to take her climbing again,' Wargowsky responded. 'What she did was quite dangerous. It is one thing for a stray dog to follow us up a mountain, but I think it would be irresponsible of us to take her to another peak and expect her to climb with us.'

Unwilling to let Baru forget her mountaineering days, Wargowsky maintains that he'd love to take her on a long hike, such as the Everest Base Camp trek. 'I will be working in Nepal/Tibet on three trips in the next year, so I will get to see her several times. I'm REALLY excited to see her again!' he said.

Did Baru's story change local people's perceptions of stray dogs in Nepal? 'I think that the locals' views definitely changed somewhat. The general attitude toward her changed from tolerance/indifference to reverence,' Wargowsky explained. 'She was allowed in tea houses and restaurants with us. She was quite the local celebrity.' Baru's celebrity status looks set to increase, with whispers of a book and feature film about her climb.

One of the hardest parts of guiding and traveling extensively over the last 10 years, Wargowsky commented, was the difficulty that this presented in getting his own dog. 'That changed recently when my fiancée and I finally decided to settle down in Seattle. Now that we have a year-round home we can have a dog. We rescued a street dog from a local animal shelter about a year ago, and she is amazing.'

Wargowsky would like to bring people's attention to StreetDogCare.org. 'This is a wonderful organisation in Kathmandu that is helping stray dogs. Since the Baru story came out, we have raised enough money to vaccinate over 850 dogs. Street Dog Care helps dogs in need and helps people in Nepal, and internationally, adopt dogs in need of a home.'