Collapsing iceberg arch

I have been watching some of the videos on YouTube of collapsing ice fronts, rolling icebergs and iceberg arches giving way -- now that Arctic cruises are immensely popular, social media are full of snippets of film of "exciting" ice front events and of boats getting rather too close to the action.  There have been some close shaves -- members of the public (and even tour operators) seem to have little idea what natural forces are being unleashed when thousands of tonnes of ice fall into the water. The resultant displacement waves are quite high enough to wash people off rocks where they may be standing, or to turn boats over -- as I tried to demonstrate in my novel "Acts of God".

Anyway, people scream, shout and clap -- and gasp with relief when they manage to escape big waves that threaten to overtake their rapidly retreating boats. But one day there will be a big accident, because tidewater ice edges have become rather too popular with adrenalin junkies........

In principle, I don't have a problem with people getting close to glaciers and developing some understanding of how glaciers work.  And tour operators should certainly be informing as many people as possible about accelerating glacier retreat and the link with global warming.  Sadly, there is too much junk science around -- the fact that an iceberg rolls over, or an arch collapses, or a glacier front suffers a sudden catastrophic failure, does not in itself indicate that this is a "global warming event".   This is all perfectly normal glacier and iceberg behaviour -- and these things happen whether a glacier is advancing or retreating in a deep water situation.

The picture above is from one of the videos,  showing a big chunk of ice falling from an arch -- it would not have been a good idea to be beneath it in a kayak (or any other craft) at the time!  Over the next minute or two, after this photo was taken, the arch lost more and more of its mass in a welter of falls big and small, until it completely disappeared.  Then, of course, the remaining parts of the iceberg made major readjustments by rolling in the water, surrounded by a great apron of brash ice.