The Science of Snowflakes

Snow Flakes Snow Crystals Science Caltech physics professor Kenneth G. Libbrecht
Kenneth G. Libbrecht

Simple Prisms
Snowflakes are not frozen raindrops (that is better known as sleet). They form when water vapor condenses directly into ice, which happens in the clouds. In their most basic form, snow crystals are hexagonal prisms like the sample, above, but other, more complex forms are famously possible.

Get the Latest Photos from
Get TIME photos and pictures of the week delivered directly to your inbox.