He predicted dozens more climbers would take advantage of the clear conditions over the next few days to launch their attempts on the summit.
The climbers take turns, with one going up and the other holding the safety rope.
So high is Mount Everest that climbers can take only a couple of steps per minute as they near the summit.
After all this effort, the climber sometimes takes his or her final step to triumph and falls for a mile or so.
Experienced climbers always took the lead, working out the route.
The trek can be completed in one day, while the average climber would take two days one night.
In this case it is perhaps best if hill-walkers and climbers took John Allen's advice on approaching the sport with the right attitude.
"Young climbers reared on bouldering are more gymnastic and take greater risks," said Greene.
I was prepared for this, having read that the climbers take a while to establish their roots.
Most climbers now take five days to make the 31-pitch ascent, bivvying each night and hauling food up the rock with them.