Jon Eckberg They are known as “drain holes”. It’s where warmer surface water drains through the ice. This mostly happens when the ice is new and fairly thin, and you get a day with warmer weather and a little rain.
I’ve seen car-sized holes melted in the ice in New England. The claim was that there must be an underwater spring pushing warm lake water upward. Not sure if that is the right explanation but it beats the runner up; a UFO with a working thermopile.
Lars Fosdal 
You need to leave a note: “Mandelbrot fell here”
LikeLike
“Help, I’m stuck inside this Mandlebrot set and I can’t get out!”
LikeLike
Slukehull kalles de der (drenerer overvann) pleier selv å sammenligne de med neuroner 🙂 men Mandelbrots fra nå.
images.google.no – Bilde: Neurons | BioNinja
LikeLike
well they certainly aren’t integer.
LikeLike
Do I need a 6P to know what these are Lars Fosdal
LikeLike
Jon Eckberg They are known as “drain holes”. It’s where warmer surface water drains through the ice. This mostly happens when the ice is new and fairly thin, and you get a day with warmer weather and a little rain.
LikeLike
I’ve seen car-sized holes melted in the ice in New England. The claim was that there must be an underwater spring pushing warm lake water upward. Not sure if that is the right explanation but it beats the runner up; a UFO with a working thermopile.
LikeLike
Wolfgang Rupprecht warmer water is spot on. Skaters often use the Swedish term “fräthål”, frät might be translated to melting (I guess). Swedish only bit great source http://www.thinkice.com/glaciology/sv/praktiskisbedomning/syn/index.htm
LikeLike
thinkice.com – Praktisk isbedömning lektion 3 – Syn
LikeLike