It is completely understandable. I would place a comma after Glacier.
Student or Learner
I have a question about the noun "run" here:
"I relaxed while the others took a ski run down the Le Conte Glacier then joined them as they were returning."
I cannot find a good dictionary definition that fits this usage. The closest definition is running with two feet. Yet, "run" as used in the example seems to mean sliding down a slope on a pair of skis. Could it be technical jargon?
Is there a dictionary definition for this usage of "run"?
That definition refers to the structure for skiing. The "ski-run" in the phrase "take a ski-run" refers to the activity of skiing.
But, in "take a run down the slope", the "run" refers to an activity (of running). Yet you claim that in "take a ski-run down the slope", "ski-run" refers to a structure?
"to take a run" doesn't have to involve using your feet, in plimsolls, pounding the pavement. I can take a run out in the car. I can take a run down a ski slope. I am not "running" in the classic sense of the word in either case. I have skied for years and I can assure that you "a ski run" is the piste on which people ski and also an instance of skiing down a particular run.
Whilst not wrong, I find the original sentence a little unnatural. I would use "I relaxed while the others skied the Conte Glacier ...", "I relaxed while the others skied down the Conte Glacier ..." or "I relaxed while the others did the Conte Glacier run ...".
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.