The cache wasn't at the boot rock, it was either in the Auspiya valley (where they spent their previous night, scenario A
), or according to Teddy & Igor Pavlov's book/theory, on the slope where the tent was later "planted" (scenario B
These values depend on where exactly their camp was etc. but here's what I gathered from a topographic map:
|Camp in Auspiya valley and labaz (scen. A)||600 ± 50m|
|"Dyatlov Pass" (that they apparently missed or avoided)||~780m|
|Tent (labaz in scen. B)||~880m|
|Cedar in Lozva valley||~650m|
According to this data, "retaining elevation gain" can't really be a reason to camp on the slope, because they had no reason to gain this elevation. If their cache was in Auspiya valley and their destination was the Lozva valley (as their planned route shows), why climb to where the tent was found?
If on the other hand they set up the cache on the slope for some reason, and then descended to the Lozva valley to camp, then of course the earthquake / rock slide / avalanche risk is not there. Even in this scenario, I don't understand why they would want to set up the cache there... In the diary the previous day, Igor writes that he can't even begin to think about setting up the cache on the ridge (that was near the pass, but the terrain is similar to where the tent was found).