Each set of three images is a single snowflake viewed from three angles by the Multi-Angle Snowflake Camera developed at the University of Utah and spinoff company Fallgatter Technologies.
Credit: Tim Garrett, University of Utah.
The system consists of three high speed cameras, separated by 36◦ but all aimed at the same spot. If a snowflake falls through the sweet spot at the focal point, the cameras are triggered by near-infrared motion sensors. Those same detectors measure the falling speed of the snowflake as it passes by. It took two months of continuous operation and a shutter speed of 1/25,000th of a second to obtain images like the one above.
Besides providing fascinating images, the MASC gives new insight into storm formation and duration, which depend in large part on the types of hydrometeors they contain. Snowflakes can also scatter electromagnetic waves to a greater or lesser extent depending on their shape, making this sort of data important for a variety of commercial uses.
By the way, you can buy your own MASC, if you're so inclined, from Fallgatter Technologies.