I love this video of an iceberg collapsing in on itself in Wilhelmina Bay, Antarctica. (Word of warning, the people filming this loved the experience even more than I loved watching it, so much so that you may want to turn your speakers down.)
There are two kinds of icebergs, tabular and non-tabular. The tabular ones are what they sound like, big flat sheets of ice. Non-tabular are different—irregular shapes that become even more irregular as bits and pieces of them melt. Judging by the arched shape this iceberg had taken on, it probably falls into the non-tabular category. Implosion happens when melting weakens key structural support within that shape and bits of the iceberg begin to crash in on itself, accelerating the breakup. Both tabular and non-tabular icebergs and catastrophically fail like this, though.
Another fun iceberg fact: There are six size categories we sort icebergs by. Four of them have pretty predictable names: "Small", "Medium", "Large", and "Very Large". But below "small" are two size categories with a little more whimsy.
Icebergs with a hight of less than 3.3 feet and a length less than 16 feet are called "Growlers".
If the height shorter than 16 feet and the length shorter than 49 feet, then the iceberg is called, adorably, "a Bergy Bit". Yes, that is a technical term.