University of Utah researchers developed a high-speed camera system that spent the past two winters photographing snowflakes in 3D as they fell – and they don’t look much like those perfect-but-rare snowflakes often seen in photos.

NASA and the U.S. Army helped fund development of the camera, and the National Science Foundation funded the observations. The goal is to improve computer simulations of falling snow and how it interacts with radar. That should help improve the use of radar for weather and snowpack forecasting, and reveal more about how snowy weather can degrade microwave (radar) communications.

The Multi-Angle Snowflake Camera (MASC) includes three, industrial-grade, high-speed cameras: two 1.2-megapixel cameras and a 5-megapixel camera, plus two sets of two motion sensors to measure the speed of falling snowflakes. The camera has a ring-shaped housing measuring about 1 foot wide and roughly 4 inches tall. The three cameras are mounted on one side, each separated by 36 degrees and pointed toward the center.

The multi-angle camera takes only black-and-white images because that gets more information; color filters block some light from images. The snowflake camera also has an extremely fast exposure time of up to one-40,000th of a second so it can capture pictures of fast-moving snowflakes in free-fall without blurring them.

Falling snow affects both microwave communications and weather-forecasting radar (which uses microwaves), yet the big problem is there is a very poor sense of how microwave radiation interacts with complex snowflake shapes. Errors in snowflake shape and size lead to errors in forecasting snowfall amounts and locations.

Source