It's possible the snow slab melted enough to blow or slide away during those 24 days, but then we're making an assumption that it existed in the first place. Which is no different from assuming the wind made a low frequency sound that scared the hikers out of the tent, or fill in whatever missing X caused them to leave the tent.
I think there's lots of odd things that go unexplained even if one can think of a reason to leave the tent like a small avalanche. Why were the two Yuri's left to attend a smile fire that they froze around? Why were the four found in the ravine several meters from the alleged snow den? Why did the lead investigator think that a radiation test in the middle of nowhere was necessary? Did he really see burned tree tops? Unfortunately, the pictures that are available today are very incomplete, including pictures of the tent, footsteps, bodies where they were found, etc.
Which raises another question. Do we have all the papers and photos from the original case?