The family and partner of 44-year-old Robin Fisher, a U.K. national, have confirmed the experienced climber has died on Mount Everest in Nepal on Saturday morning.

Kristyn Carriere, who is from Edmonton but moved to the U.K. a decade ago, says Fisher passed away shortly after summiting.

It’s believed he succumbed to altitude sickness at 8,600 meters.

Carriere says the pair were together for four years and loved to go on adventures and run marathons.

Climbing Mount Everest was a dream of Fisher’s so the pair embarked on the journey to the mountain's base camp together on April 17.

It was there they parted ways and Fisher continued his quest, eventually reaching the top of the mountain at 8:30 a.m. Nepal time on May 25.

Tragically, he fell ill and died minutes later.

Fisher’s family, who are from Birmingham, released a statement:

Robin Haynes Fisher, aspirational adventurer, lived life to the full. He achieved so much in his short life, climbing Mont Blanc, Aconcagua and Everest. He was a "tough guy", triathlete, and marathoner. A champion for vegetarianism, published author, and a cultured theatre-goer, lover of Shakespeare. We are deeply saddened by his loss as he still had so many more adventures and dreams to fulfill. Everyone who ever met him in any capacity will always remember the positive impact he had on their lives. Robin is a much loved and loving son, brother, partner, uncle, and friend.

There have been reports of overcrowding near the summit as depicted in a photo from mountaineer Nirmal Purja that went viral showing the long queue of people trying to get to the top.

Fisher’s last post on his Instagram page was six days ago. He expressed concerns about overcrowding at the summit and decided to delay his ascent in hopes the line of people would thin out.

 
 
 
 
 
 
 
 
 
 
 
 
 

Climbed up to camp 3, 7500m but the jet stream had returned closing the summit after only 2 days so I descended to basecamp. Around 100 climbers did summit in those 2 days with sadly 2 deaths, an Indian man found dead in his tent at camp 4 and an Irish climber lost, assumed fallen, on his descent. A go fund me page has been set up for a rescue bid for the Irish climber but it is a well meaning but futile gesture. Condolences to both their friends and families. Both deaths happened above 8000m in the so called death zone where the majority of deaths of foreign climbers happen. Around 700 more people will be looking to summit from Tuesday the 21st onwards. My revised plan, subject to weather that at the moment looks promising, is to return up the mountain leaving basecamp Tuesday the 21st 0230 and, all being well and a lot of luck, arriving on the summit the morning of Saturday the 25th. I will be climbing with my Sherpa, Jangbu who is third on the all time list with an incredible 19 summits. The other 4 members of our team decided to remain on the mountain and are looking to summit on the 21st. My cough had started to return at altitude so I couldn’t wait with them at altitude for the window to open without the risk of physically deteriorating too much. Furthermore as I had missed due to sickness the earlier camp 3 rotation best practice was for me to descend to allow my body to recover from the new altitude high so I could come back stronger. This was not an easy decision as the 13 hours climbing from basecamp to camp 2 in a day was the hardest physical and mental challenge I had ever done, now I have it all to do again. Finally I am hopeful to avoid the crowds on summit day and it seems like a number of teams are pushing to summit on the 21st. With a single route to the summit delays caused by overcrowding could prove fatal so I am hopeful my decision to go for the 25th will mean fewer people. Unless of course everyone else plays the same waiting game. #everest #everest2019 #lhotseface

A post shared by Robin (@1c0n0clast22) on

Authorities say an American climber, Don Cash, also died of altitude sickness while descending Mount Everest on Friday.