A week before the favourable window to reach the top of the world shuts down, a staggering 250 climbers were waiting at the final camp on Tuesday night, hoping to reach the top of Everest by Wednesday morning.

However, the unusually high number of aspiring climbers aiming to make it to the top on the same morning has once again raised fears of overcrowding—and a traffic jam—at the steep and dangerous slope of the world’s highest peak.

According to government officials, the 250 climbers have been camping at the 7,900-metre point of the mountain, popularly known as Camp IV, to begin their final summit push on Tuesday night.

If all 250 climbers successfully scale the summit on Wednesday, that would make it the largest single-day ascent of Everest. In 2012, 264 climbers made their final push for the summit. That year, 179 climbers successfully reached the top, but not before causing what many referred to as a “traffic jam” on the Hillary Step—a vertical rock with a sharp slope considered one of the most dangerous parts of the climb—due to a small weather window.

The same thing is bound to happen again on Wednesday, and some officials say there is a risk of heavy traffic, potentially causing risks to climbers if the weather suddenly turns bad.

"The Camp IV may be busy on Tuesday night but the influx is manageable if the weather behaves well,” said Ang Tshering Sherpa, chairman of Asian Trekking and past president of Nepal Mountaineering Association. “But a sudden deterioration in weather may make things difficult.”

Other officials, however, said the huge number of climbers waiting to make a push at the final camp is nothing to worry about.

“There is a big crowd on the Camp IV,” said Gyanendra Shrestha, a government liaison officer stationed at the Everest base camp. “But we don’t expect all of them to go up at the same time. Climbers keep going up and come down simultaneously.”

Shrestha said that Everest has seen such a crowd before and it occurs when the “climbing window” gets narrow mainly due to bad weather condition.  

Everest climbers, who spend nearly a month at the Everest base camp in preparation to climb the mountain, normally have a two-week window to reach the summit before pre-monsoon kicks in. This season, the Everest climbing season started on May 14, with a team of eight rope-fixing high-altitude climbers opening a climbing route. The first two-day weather window was closed on May 16 after over 150 world climbers made it to the summit.

The second climbing window opened on Monday. Ang Tshering said there was no exact record of climbers’ success on Tuesday but the number could be huge.

According to Ang Tshering, there were around 200 climbers on Monday night waiting for the summit push but most of them had to return due to strong wind. That, he said, could be one of the reasons for the high number of aspiring climbers at the final camp.

Although the number of climbers who scale Everest during the final week of window has grown in recent years, overcrowding at high altitude poses danger to both experienced climbers as well as guides accompanying them. During the final phase of ascent, climbers are exposed to risks of thin air and many could run out of oxygen as well if they have to wait for long hours for their turn to reach the top—as well as to make it down from the summit.

Ang Tshering said that an equal number of climbers will assemble on Camp IV on Wednesday night as well because the season is expected to close by May 26.

In May 2012, four climbers—Ha Wenyi from China, Eberhard Schaaf of Germany, Nepal-born Canadian Shriya Shah and South Korean mountaineer Song Won-bin—died from exhaustion and altitude sickness while descending from the summit.

According to the Department of Tourism, 381 individuals have been cleared to climb the Everest this spring season. As each climber hires at least one climbing guide, the total number may reach to 1,000, the department has estimated. For the past three years, the success rate on Everest has been close to 70 percent.

While hundreds waited on Tuesday to seek glory by scaling Everest, veteran climber Kami Rita Sherpa reached the summit early morning, for the second time in a week, taking his record of setting foot on the top of the world to an awesome 24 times.

Kami Rita, 49, returned from the 8,848-metre peak on May 15. But after a brief rest, he set off for the mountain on May 18 to repeat the feat.

Kami Rita, who currently works as a senior climbing guide at Seven Summit Treks, scaled Everest for the first time on May 13, 1994.