pipkrake
Needle ice; ice structures formed when the air temperature is below 0℃ and the soil is not.
countable, uncountable
The most widespread and familiar example of this process is that associated with the growth of needle ice or pipkrake (Figure 5.15), needles of clear ice commonly exceeding 5 cm in length. Growth of pipkrake is favoured by supercooling of the soil in conditions of marked radiative heat loss from the surface […]
Where it comes from
From Swedish pipkrake, from pip (“tube”) + krake (“thin, fine, weak”), coined by Swedish botanist Henrik Hesselman in 1907.
Adapted from the Wiktionary entry pipkrake (CC BY-SA 4.0).