The special "icefall doctors", who use expert knowledge of crevassed icefalls to attach ropes and ladders along the route, cannot find any way to get around the ice block that is stopping climbers just before the first camp.
The block must melt, say the icefall experts.
Normally, they would have secured the route to the third of four camps at this time of year.
Purnima Shrestha, an experienced climber from Nepal who is preparing to reach the summit for the sixth time, fears there could be "traffic jams" on the way to the summit this year.
