(CNN) Three of them died chasing a dream. The fourth fell to his death helping others chase theirs.

Rescue efforts are still ongoing for two missing climbers on Mount Everest after a grim week that saw three tourists and a Sherpa lose their lives in four days

The death toll is a chilling reminder of the enormous hazards Everest poses, even to some of the world's most experienced climbers.

Now details are emerging about how the world's highest mountain took its latest victims. Here's a closer look at each.

Eric Arnold, 36

Eric Arnold was a triathlete based in Rotterdam. He is believed to have died from a heart attack.

Eric Arnold, a Dutch citizen, died Friday during his descent, having reached the summit in what his team leader described as a "childhood dream."

"Tragedy struck our team," expedition leader Arnold Coster said in a post on his blog

"Descending from the summit he became slower and slower and it became clear that something was wrong. His Sherpa who was climbing with him from the beginning requested to send an additional Sherpa up with more supplementary oxygen to help him down," Coster explained, adding that Arnold was able to make it down to the next camp.

"We brought him to his tent, gave him more oxygen, lots off drinks and food and it looked like he was recovering," Coster said.

But Arnold took a turn for the worse and died that night in his tent, he said. He is believed to have died from a heart attack.

Arnold was a triathlete based in Rotterdam, according to his Twitter bio. A post on his Twitter account showed a photo of Arnold at the summit, although it was unclear if it was Arnold himself who posted it.

Bergbeklimmer Eric Arnold bereikt top Mount Everest bij vijfde poging https://t.co/oeswLrfXyd pic.twitter.com/991NvMg6Op — Eric Arnold (@EricArnold8850) May 20, 2016

Another post read "Off we go!!" with a picture of the team at camp.

Off we go!!! Zondagnacht 02.00 vertrek. Ma-C2 Di -C2 Wo-C3 Do-C4 vrijdagnacht top!! pic.twitter.com/41ThbFSd70 — Eric Arnold (@EricArnold8850) May 15, 2016

Colorado-based mountaineer Jon Kedrowski, who said he had climbed with Arnold, tweeted that he was "very bummed" to hear the news.

I knew Eric Arnold and climbed with him in Nepal in 2012 & 2015. very bummed when I heard the news 😥 https://t.co/ylNCapffcs — Jon Kedrowski (@DrJonKedski) May 22, 2016

Maria Strydom, 34

Maria Strydom said she was climbing Everest to prove vegans are not weak.

It was a tough week for Coster's team. The following day, they lost another member -- Australian citizen Maria Strydom, known by her friends and family as Marisa, who died after suffering altitude sickness.

"These tragic events numbed the whole team and our thoughts are with their family and friends. May they rest in peace," Coster said.

South African-born Strydom worked as a finance professor with the Monash Business School in Melbourne. She had told the school in an interview that she and her husband, Robert Gropel, were climbing Everest to prove that vegans are strong.

"It seems that people have this warped idea of vegans being malnourished and weak," said Strydom, who added that she and her husband had received countless questions about their iron and protein levels.

"By climbing the seven summits we want to prove that vegans can do anything and more," she said.

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Strydom reached Everest's South Summit on Friday but decided to turn around and descend when she wasn't feeling well, according to Coster's post . Several Sherpas and her husband struggled to carry her down the mountain, but she collapsed the next morning, Coster said.

Gropel, her husband, was evacuated to Kathmandu the next day by helicopter, said Coster, who was assembling a rescue team to retrieve Arnold's and Strydom's bodies.

Strydom's family was informed that the recovery team had retrieved her body and moved about 300 meters down the mountain but stopped due to bad weather and heavy snow. They hope to get down to Base Camp II tomorrow if weather clears and from there get a helicopter out.

Her mother, Maritha Strydom, told CNN that her daughter first became interested in climbing around 12-years ago. The first mountain she climbed was Mt. Warning near Brisbane.

"I was worried about her back then because I'm the most protective mother. After that, she went on to climb in New Zealand and the Andes in South America," she said.

"We were a very close-knit family. We took Maria all over the world since she was little. She has the strongest personality since she was born ... She was very talented and always wanted to be the best. She had more energy than anyone."

Photos: Exploring Mount Everest The journey to the summit of Mount Everest is a challenge an increasing number have taken on since the summit was first reached in 1953 by Sir Edmund Hillary and Tenzing Norgay. Until the late 1970s, only a handful of climbers per year reached the summit. By 2012 that number rose to more than 500. Hide Caption 1 of 23 Photos: Exploring Mount Everest Explorers are seen in 1922 at Camp II on the East Rongbuk Glacier. That same year, seven Sherpas were killed when they were caught in an avalanche during an expedition led by George Mallory. Hide Caption 2 of 23 Photos: Exploring Mount Everest George Mallory and Edward Felix Norton reach 27,000 feet on the northeast ridge of Everest in 1922. They failed to reach the summit. Hide Caption 3 of 23 Photos: Exploring Mount Everest Mallory returns to Everest In June 1924. He's seen here with his climbing partner Andrew Irvine at base camp. This is the last photo of the the two before they disappeared on the mountain. Mallory's body was found 75 years later, showing signs of a fatal fall. Hide Caption 4 of 23 Photos: Exploring Mount Everest Mountaineers are seen preparing to leave their camp during one of Eric Shipton's early expeditions on Everest in the 1930s. While Shipton never made it to the summit, his exploration of the mountain paved the way for others. Hide Caption 5 of 23 Photos: Exploring Mount Everest Shipton leads an expedition exploring the Khumbu Glacier icefall in November 1951. Hide Caption 6 of 23 Photos: Exploring Mount Everest Shipton is also known for discovering and photographing footprints of an unknown animal or person, like this one taken in 1951. Many attributed these to the Yeti, or Abominable Snowman. Hide Caption 7 of 23 Photos: Exploring Mount Everest Edmund Hillary sits at base camp in May 1953 before heading out on what would become the first successful ascent to the top of the world. Hide Caption 8 of 23 Photos: Exploring Mount Everest Hillary and Nepalese-Indian mountaineer Tenzing Norgay climb beyond a crevasse on Mount Everest in 1953. Upon meeting George Lowe, who had climbed up to meet the descending duo, Hillary reportedly exclaimed, "Well George, we knocked the bastard off!" Hide Caption 9 of 23 Photos: Exploring Mount Everest Members of a U.S. expedition team and Sherpas are shown with their climbing gear on Everest. The team, led by Jim Whittaker, reached the top on May 1, 1963, becoming the first Americans to do so. Hide Caption 10 of 23 Photos: Exploring Mount Everest Whittaker's team members climb Everest's West Ridge in 1963. Hide Caption 11 of 23 Photos: Exploring Mount Everest On April 5, 1970, six Sherpas died in an avalanche at the Khumbu Icefall. The icefall, at the head of the Khumbu Glacier, seen here in 2003, is one of the more treacherous areas of the ascent. Hide Caption 12 of 23 Photos: Exploring Mount Everest British Army soldiers and mountaineers John "Brummie" Stokes and Michael "Bronco" Lane above the icefall at the entrance to the West Col (or western pass) of Mount Everest during their successful ascent of the mountain. The joint British-Nepalese army expedition reached the summit on May 16, 1976. Hide Caption 13 of 23 Photos: Exploring Mount Everest In 1978, Reinhold Messner makes the first ascent without supplemental oxygen. Messner is seen here at Munich Airport showing reporters his frozen thumb after climbing to the top of Nanga Parbat in Pakistan, alone and without an oxygen mask. Hide Caption 14 of 23 Photos: Exploring Mount Everest French climber Jean-Marc Boivin becomes the first person to paraglide from Everest's summit in September 1998. Hide Caption 15 of 23 Photos: Exploring Mount Everest The 1996 climbing season was one of the deadliest, when 15 people died on Everest, eight in a single storm in May of that year. Hide Caption 16 of 23 Photos: Exploring Mount Everest Francys Distefano-Arsentiev became the first American woman to reach Everest's summit without bottled oxygen on May 23, 1998. However, she and her husband, Sergei Arsentiev, never made it off the mountain. They died after becoming separated while attempting to descend in the dark. At least one climbing party found Francys barely conscious, but there was nothing they could do to save her. Her husband's body was found years later. It is believed he fell while trying to save his wife. Hide Caption 17 of 23 Photos: Exploring Mount Everest Pemba Dorje Sherpa and Moni Mulepati became the first people to get married on Everest's summit, on March 30, 2005. The couple are seen here waving from base camp on June 2, 2005. Hide Caption 18 of 23 Photos: Exploring Mount Everest Sherpa climbers pose at Everest Base Camp after collecting garbage during the Everest cleanup expedition on May 28, 2010. A group of 20 Nepalese climbers collected nearly two tons of garbage in a high-risk expedition to clean up the world's highest peak. Hide Caption 19 of 23 Photos: Exploring Mount Everest Mountaineer Ralf Dujmovits took this image of a long line of climbers heading up Everest in May 2012. Hide Caption 20 of 23 Photos: Exploring Mount Everest Jordan Romero became the youngest person to reach the summit, at age 13, on May 22, 2013. Jordan, right, is seen here on the summit with one of the Sherpas who helped him make the ascent. Hide Caption 21 of 23 Photos: Exploring Mount Everest Yuichiro Miura, became the oldest person to summit Everest, on May 23, 2013, at the age of 80. Hide Caption 22 of 23 Photos: Exploring Mount Everest Malavath Poorna, left, holds up her national flag on May 24, when the 13-year-old daughter of poor Indian farmers became the youngest girl to climb Everest. Hide Caption 23 of 23

Subash Paul, 44

Everest struck again on Sunday, as abrupt changes in weather conditions made the climb even more arduous that usual.

Indian climber Subash Paul (far left) died Sunday. He is pictured here with Paresh Chandra Nath, second from right, and Goutam Ghosh, third from right, who are missing.

Indian national Subash Paul died at Base Camp II -- at an elevation of about 24,600 feet -- Sunday from altitude sickness, according to Wangchu Sherpa, Managing Director of Trekking Camp Nepal.

Paul was part of a team of four Indian climbers and four Sherpas that also saw two members -- Paresh Chandra Nath and Goutam Ghosh -- go missing Saturday night.

"It is not clear what happened. We believe the weather suddenly deteriorated at some point, and the team lost direction," Wangchu Sherpa said.

Indian climber Chetana Sahu at the Everest Base Camp after being rescued from near the summit.

Phurba Sherpa, 25

Pictures of the team emerged Tuesday, showing a happy group about to set off. But the photos also revealed fatigued climbers, visibly depleted by Everest's harsh conditions.

A crew member, Phurba Sherpa, also fell to his death on Thursday. The 25-year-old had been working to fix a route about 150 meters below the summit when he fell, according to Mingma Sherpa, the Nepal rescue team leader who was at the Everest Base Camp.

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