Khumalo posted an update on the Ubuntu Everest Facebook page on Thursday to say that the expedition had officially been cancelled.
“We have two options, come back home immediately or consider doing another mountain before we return.”
The mountaineers intended climbing another mountain as they had already acclimatised to the high altitude.
“They say the mountain is open but it certainly is not safe for any of us to attempt it this year,” Khumalo, who sought to be the first black woman to summit Everest, said.
On Friday an ice avalanche killed 13 Nepalese guides around 500 metres from Vilane and Khumalo, who were at base camp. There was concern that another avalanche could follow.
Khumalo said the Nepalese tourism minister went to the mountain on Thursday.
“Sherpas presented their demands and at the end threatened to stone the minister if he did not sign their petition.”
Ubuntu Everest also posted an update from mountaineer Alan Arnette.
He said that, from his own experiences and judgement, there were three reasons for the Everest 2014 season from Nepal being halted.
These were the hazard of further avalanches, the importance of paying respect to those killed in the avalanche and the Sherpa people of eastern Nepal, who regard the mountain as sacred.
In addition, Sherpa guides were dissatisfied with the pay they received and the compensation given to the families of those killed.
“Threats were made to Sherpas who didn’t agree to stop climbing threats against them and their families,” Arnette said.