For those who have not done Jackson Blue when the flow is at normal strength, not only can you not silt the cavern out, in much (not all) of it you can use an exit strategy not taught in cavern classes--close your eyes and hover. You'll be out in no time. You may have bounced off a few rocks on the way, but you will be out. The hard part is staying in for the safety stop. You have to know where to hide.Not being cavern certified, I have no knowledge of Jackson Blue, but from what others have posted it sounds like that's a good place for one's first cavern dives.