Floes occur during heating and drifting apart previously closed ice at the poles or on rivers, lakes, etc.. A phenomenon is so far the occasional occurrence of circular ice floes, so-called Eiskreise.
On rivers floes driving a threat to bridges can be. You can accumulate a so-called meltdown between the pillars and thus exert high loads on the structure.
Also the huge continental ice breaking off from the Arctic or Antarctic ice ( icebergs ) are sometimes colloquially referred to as the ice floes.
The largest iceberg was ever observed, was spotted in 1956 in the Antarctic. He had a length of 335 km and a width of 97 km, ie an area of approximately 31,000 km ², almost as large as the state of North Rhine -Westphalia.