There will be quibbling (so I'll start it now
):
I claimed a previous 'potential blocker' didn't actually block anything, it merely slowed things down for a day or so, as half of it appears to have started crumbling upon setting up the blockage. Some seem to claim it blocked the channel for a day or so.
To achieve blockage, will 'day apart' images need to show the Very Big Chunk - "VBC" (or remaining piece of it) - unmoved and 'fully' intact on successive images? B_, it is your call.
I think I've seen this happen, by the way: a single-floe blockage in nares Strait that lasted a day or two before collapsing.
___
"VBC" - not to be confused with the
Vienna Boys Choir, etc.