Not being a climber, why would someone leave an ice cave offering protection from the elements to build another one elsewhere close by? Hyposia? Hope of it being seen from above?
There is only amateur speculation at this point as to the two caves, why the climbers were separated, etc. The sheriff is holding a news conference at 9 AM today (PST) and will supposedly address some of these issues.
The body of James will be airlifted off the mountain today, weather permitting. Perhaps he left a note explaining the situation. Perhaps there are clues in and around the two caves which would help piece together the series of events. Only the authorities know.
I've been following this story closely and at this point, information is being held very close to the vest by authorities and the search will continue for the remaining two climbers, who are assumed to be still alive until evidence is found to the contrary.
"why would someone leave an ice cave"
I'm guessing he was losing patience from being alone in the first cave, had a localized break in the weather that allowed him to reach the summit, but then found that summit winds were simply too much, so started a second snowcave just over the summit ridge.
I've been 50 feet short of a summit in 20-30MPH winds, then reached the top only to find 80-100MPH near-continuous.