Roland Yearwood, a 50-year-old physician from Alabama, died while climbing Mount Everest, not far from the mountain's peak. Yearwood is pictured here camping during a different trip. (Family photo via Alabama Media Group )

Three Mount Everest climbers died and a fourth was missing as high winds eased and opened fleeting windows of good weather for teams to push toward the top of the world’s tallest peak, authorities said Sunday.

Roland Yearwood, a doctor from Alabama who returned to Everest after surviving the earthquake-triggered avalanche in 2015, died not far from the summit on the Nepal side early Sunday, according to Nepal tourism officials and his trekking company.

Slovak mountaineer Vladimir Strba also died Sunday, and search operations continued for an Indian climber who was separated from his guide on Saturday. And on the Tibet side of the mountain, a 54-year-old Australian climber, Francesco Enrico Marchetti, died after suffering altitude sickness, according to a report in the Himalayan Times.

This year, a record number of climbers are trying to scale the world’s highest peak, with 375 foreigners issued permits, the most since 1953. The high volume of traffic has fueled concerns about safety issues on the mountain, which continues to suffer environmental degradation.

Mountaineers ascending to the top confirmed this season that little remains of the famed “Hillary Step” — the wall of rock that was once the final test of endurance before the summit and named for Edmund Hillary, who in 1953 became the first to reach the Everest summit, with fellow climber Tenzing Norgay.

An estimated 60 climbers made the summit in Nepal on Sunday alone, authorities said.

“The weather has been pretty bad, especially with high winds, but there were some little keyholes which climbers have been lucky to take advantage of,” Tendi Sherpa, a longtime guide, said in a Facebook direct message from base camp. “Several teams got lucky but there are also many climbers who had to turn around half way to the summit due to high winds.”

Tendi Sherpa said Sunday was a busy day for helicopter evacuations, mostly for altitude-related sicknesses, frostbite and snow blindness. He said several teams were planning on climbing all night and expect to reach the summit Monday morning.

Meanwhile, Chhewang Sherpa, managing director at Arun Treks, said Indian climber Ravi Kumar made it to the summit at 1:28 p.m. Saturday but grew tired on the descent and had to lie down. His Nepali guide was also feeling sick and decided to descend to call for rescue, leaving Kumar with a supply of supplemental oxygen. The guide later stumbled into the high-altitude Camp 4, but Kumar has not been found.

Two Everest climbers died earlier this year. Famed Swiss mountaineer Ueli Steck fell while on a training run on a nearby peak earlier in the season, and Min Bahadur Sherchan, an 85-year-old mountaineer, died of a heart attack at base camp on May 6.

Climbing Everest is an inherently dangerous activity with risks of sicknesses related to high altitude such as cerebral edema, a swelling of the brain that can be fatal. Every spring climbing season in recent years has claimed lives, with more than 280 dying over the years.

Yearwood, 50, a doctor at Georgiana Medical Center in Alabama, was part of a team led by American climber Daniel Mazur for the expedition firm SummitClimb, according to its Nepal-based partner, Murari K. Sharma.

Yearwood was trained as a doctor in London and New York and eventually settled in southern Alabama, where he had been a primary care physician for 20 years, according to his biography on the rural health center’s website. He was married to another physician, Amrita, and has two college-age daughters.

In 2015, he was on the mountain when the devastating earthquake in Nepal triggered an avalanche that killed 18 climbers. He was eventually brought down to safety.

“He is always calm,” Amrita Yearwood told the local news site AL.com at the time. “He does a lot of sports. He is adventurous. He doesn’t get freaked out.”

SummitClimb, which has offices in Clifton, England and Lakebay, Wash., specializes in “affordable climbs and treks” and had teams on both the Nepal and Tibet sides of the mountain this year, according to its website.

On Saturday, Mazur tweeted and posted on the team’s blog that one member and a Sherpa guide had reached the top of Everest, with “more on the way.”

The entire group on Friday had made it to the mountain’s South Col area, which is around 26,000 feet. But the climbers halted there after teams received a radio call that the summit was very windy and many were turning around, according to Mazur’s social media accounts.

Gowen reported from New Delhi. Shirley Feng contributed to this story from Beijing.