American trail runner Tyler Andrews has just left Everest Base Camp in an attempt to make the fastest ascent ever to the summit and back, without supplemental oxygen.
According to the stats on his website, he set off right on schedule at 8:03 pm Nepal time:

Chart on Tyler Andrews’ website.
Andrews, 35, intends to climb through the night and reach the summit early Sunday morning in Nepal.

Tyler Andrews in Colorado last Sunday. Photo: Santiago Guerrero
No companion, support on the route
He is climbing on his own, but will count on two resupply posts at Camp 2 and Camp 4.
The American athlete will not have to deal with the long traffic jams seen on the mountain earlier this week, although he will cross paths with some teams. Some summits were reported today as well, and other climbers are in higher camps, planning to attempt the summit in the next two or three days.
You can track his progress live here.
News is also expected from Karl Egloff of Ecuador, also in Base Camp, and with the same Everest FKT in mind. He posted an Instagram story today with photos of his family and the text “this is for you all,” suggesting he is about to leave as well.
Other no-O2 climbers
A handful of no-oxygen climbers are still on the mountain. Justin Sackett of the U.S. had to return to Base Camp from Camp 3 due to a stomach bug, but he is not ready to surrender. He is feeling better now and will try to reach the summit on May 27-28.
Saulius Damulevicius of Lithuania, who aims to climb Everest without oxygen or Sherpa support, is in Camp 3.