grue

[ddon]

how is grue (loose ice flakes on ponds etc) formed. someone thinks it floats up from the bed, but I'm not buying that

[felinechums]

It's gruesome

[heathfield]

In water that is very close to freezing, ice crystals can start to form first round something that's floating in the water, or has fallen onto the surface. This could be a speck of dust or dirt, or a snowflake, etc. Once the process starts, the crystals can keep growing, forming the discs that you see. In Arctic and Antarctic seawater, it is possible for these to form beneath the surface where two different layers of water are in contact, but it's a lot less likely to happen in a pond. The proper term for this kind of ice is 'frazil ice' - a 'grue', (as in 'A Grue of Ice'), is simply something horrible, or that provokes fear, as in the word 'gruesome'