Habit follows humidity — dendrites need the wet cold.
Classified specimens by dominant habit · n = 4,180−1 °C → −22 °C grid
612
438
1,946
734
450
Needles
−4 / −6 °C
Columns
−6 / −10 °C
Dendrites
−12 / −16 °C
Sectored plates
−10 / −12 °C
Solid plates
−18 / −22 °C
46.6%
of classified crystals were dendritic
+18.4 pts above the next habit
The branched six-fold form only crowds the grid where supersaturation is high. Lower the humidity and the same temperature band returns flat plates instead.