Tallest non-tabular iceberg

Icebergs are commonly classified into two main shapes. “Tabular” icebergs are flat-topped, steep-sided slabs which are relatively thin compared to their extent. They’re found mainly in Antarctic regions and calve from floating platforms known as ice shelves. Tabular icebergs nearly always hold the record for the world’s largest icebergs and many are the size of small countries. In contrast, “non-tabular” icebergs are generally smaller and far more irregular in form. They include a variety of shapes, from domed and wedge-like structures to the dramatic pinnacles most people instinctively associate with icebergs. The tallest non-tabular iceberg was spotted off western Greenland by Commander Robertson Dinsmore of the ice breaker USCGC Eastwind in March 1957. This tower of ice rose some 167 m (550 ft) above the water – the equivalent of a 55-storey building. The International Ice Patrol considers any iceberg standing 75 m (246 ft) above the water to be “very large”, and this one was over twice that threshold.

The biggest tabular icebergs (such as B15, the largest iceberg ever), meanwhile, have been estimated to rise as much as 200 m (660 ft) above the waterline. It's worth noting that the visible portion of an iceberg above the surface usually only represents c. 10% of the total thickness, so these largest icebergs are likely around 2 km (1.2 mi) in total thickness.