More than 4,000 people have climbed the world’s tallest mountain since Sherpa Tenzing Norgay and Edmund Hillary first touched the summit of Mount Everest in 1953. That averages to about 70 people every year, with numbers increasing steadily in the last few years, as an estimated 800 people attempt to climb the peak annually and almost 700 reached the summit in 2013. And yet, only one person managed to climb to the top in the last two years, and even that, amid controversy.

This year, about 290 climbers and their 400 guides are in various camps near the summit, awaiting a favorable weather window before they make the final push. The attempts after a three-year gap come after fatal avalanches in both 2014 and 2015 killed at least 34 people, including both climbers and their guides.

An avalanche in the Khumbu Icefall area on the Nepalese side of the mountain in 2014 killed 16 guides, and last year’s devastating earthquake in Nepal sent a large amount of snow crashing into the Base Camp, in which 18 people died.

Most of the climbers this year and their guides have been on the mountain since March to acclimatize themselves for the climb.

Gyanendra Shrestha, a mountaineering official with Nepal’s Tourism Ministry, told Deutsche Welle over the phone from the Base Camp: “Icefall doctors have begun fixing the rope today. The Nepali climbers will have arrived at the summit tomorrow and the others will follow them on the 11th,” depending on the weather.

Ang Tshering Sherpa, chief of the Nepal Mountaineering Association, who is also in touch with climbers at Base Camp, told Reuters in Kathmandu that, weather permitting, the route from the South Col to the summit would be fixed on Wednesday.

“Climbers will then start making summit attempts from Thursday,” Sherpa said.

South Col, or Camp 4, is located at a height of about 26,240 feet and is the last pause for climbers before they try to reach the summit, which is 29,035 feet high.

Meanwhile, the Himalayan Times, a Nepalese newspaper, reported Tuesday that two climbers from Slovakia were trapped after an avalanche struck their route at above 23,500 feet. They both chose to climb the riskier southwest face, while most climbers choose the easier southeast route.