The three Maltese mountaineers' plans to reach Everest by Thursday have been derailed by a snowstorm.
Gregory Attard, Marco Cremona and Robert Gatt, accompanied by Brazilian Manuol Morgado and guided by mountaineering veteran Victor Saunders, rushed back to base camp from a three-day rest in a mountain lodge as there was a possibility for an early summit.
This would have been one of the earliest Everest summits for a team, and Challenge8000 would have chopped off a good 10 days from their expedition.
However, a snowstorm delayed their plans indefinitely and, writing in his blog, Mr Gatt said pushing for an early summit would be "a recipe for misadventure". There was a chance a good summit window would open after May 10, he added.
The group had spent three days in Pangboche, the highest Himalayan settlement in Nepal, where they got to rest, eat, shower in friendly surroundings and re-energise.
"We are making the best of the electricity supply and facilities available here... charging batteries, playing music through speakers, shaving, watching videos... most things that we have been deprived of for a month, Mr Cremona wrote.
Mr Cremona hoped the group was not getting too soft at the mountain lodge, mostly in view of the hardships that will follow.
"At this point of the expedition - just before the summit attempt - I'm treating Everest as an obstacle course and not the majestic natural wonder that it really is," Mr Cremona wrote in his blog.
"In my mind, Everest has already been chopped up into stages, each stage made up of particular obstacles and then ultimately into steps.... one tedious step after another, placing my boot in the footstep of the previous climber - if there are any - all of these obstacles have to be overcome over a period of four to five days. Sounds very clinical... but it actually is."
The group, currently biding its time at base camp, will have to cross the treacherous Khumbu Icefall to Camp 1, then on to Camp 2.
The most dangerous part starts here, as the party will have to tread the Lhotse Face, 1,200 metres of ice, making the climb feel like one was climbing and digging into a mirror.
This is not virgin territory, as the team has already climbed up to the 7,200 metre-high Camp 3 for acclimatisation in "Arctic conditions". However, what lies beyond Camp 3 is the ascent to the beginning of the Death Zone - Camp 4.
At this stage, the thin air means the group will have to use oxygen tanks and success will depend on whether it has enough strength after fighting a huge ice wall.
If the group is to make history, failure is not an option, according to Mr Cremona: "In a way, it is quite unfortunate that our success on this immense mountain will be judged by history as to whether we will reach the summit or not. We have already achieved a lot, personally and for our country. But the harsh reality is that it's the summit that counts."