Encore - Triangular Snow Crystal

September 21, 2019

Triangular Snow Crystal

Today and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.

Provided By: The Schwerdtfeger Library
Summary Author: Jim Foster

December 2013 Viewer's Choice Not all snow crystals look like the ones on store-front windows. The odd, triangular crystal featured above has arms that are obviously unequal in length, but it still has a hexagonal shape. So even thought the sides are dissimilar, the angles are nonetheless all the same (60 degrees). Note that the innermost hexagonal shape is very close to being symmetrical.

It’s been observed that plate-type crystals may on rare occasions assume triangular shapes when the air temperature is a little below freezing (27 F or -3 C) –- the reason for this isn’t clear. The corners of this particular crystal sprouted the miniature plates as it neared the surface.