Long, white, hair-like wisps of cirrus clouds, thicker at one end then tapering to the other. They are named after their close resemblance to actual tails of female horses. The clouds themselves are made up of primarily ice crystals. The comma-shape to the clouds is due to the fallout of larger ice crystals in an environment with vertical wind shear.
MARE'S-TAIL CIRRUS (CI)
Meaning of MARE'S-TAIL CIRRUS (CI) in English
Weather and meteorology English vocabulary. Английский словарь погоды и метеорологии . 2012