Adventure Consultants, based at Wanaka, said on its website today:
"Yesterday's devastating earthquake resulted in an avalanche from Mount Pumori which caused significant damage to the Adventure Consultants camp at Everest Base Camp. The avalanche also resulted in multiple casualties from various teams.
"We are saddened that two Nepali local staff from Adventure Consultants are amongst the fatalities. We are not yet able to post the names of those have died as these details become clear and next of kin are contacted.
"Rescue efforts are underway, however bad weather in the region is preventing helicopter access currently.
"The climbing team are safe on the mountain at Camp One where they will remain until weather improves."
Camp One is at the top of the Khumbu Icefall. Pumori (7165m) is a mountain that rises above the 5200m base camp. The base camp is on the Khumbu Glacier near the foot of the icefall.Adventures Consultants said the Everest Base Camp avalanche that killed two of its Nepali staff appeared to have been caused by a large chunk of ice being dislodged by the earthquake.
Steve Moffat, the Wanaka-based company's New Zealand operations manager, said from Wanaka he understood the avalanche consisted of a "massive blast" of powder snow triggered ice falling off Pumori and Lingtren, mountains that rise above the base camp in the Khumbu Glacier.
International media reports vary, some saying 10 and one that at least 17 people have died at the base camp.
Adventure Consultants has now lost five staff at Everest in two seasons. Three of its local staff were killed in the Everest avalanche which killed 16 Nepalese last April.
In addition to its base camp contingent, the company has 10 climbers and four guides, including expedition leader Guy Cotter, at Camp 1 at 5900m just above the Khumbu icefall.
Mr Moffat said all those at Camp 1 were safe and well. It was still early in the Everest climbing season and no teams had gone above Camp 1 in the Western Cwm yet.
"I know there's a lot of supplies at Camp 1 and Camp 2 so the people up there, there's numerous teams up there right now, they are safe where they are and they have food and fuel to survive," he said.
"I imagine areas of the Khumbu icefall will have been affected by the ground shaking causing damage to the route they take. As far as I know no one is attempting to drop from Camp 1 at this stage."
Mr Moffat said at 3.30pm today the weather this morning Nepal time was "fine".
"I believe a rescue helicopter had made it into base camp and I would imagine picking up injured people."
By Martin Johnston of the New Zealand Herald
