Multi-Angle Snowflake Camera

All images on these pages are copyright Tim Garrett, and are freely available for non-commercial or educational purposes. Otherwise, please contact Dr. Garrett through the ACCS link above.

The Particle Flux Analytics Multi-Angle Snowflake Camera (MASC) takes 9 to 37 micron resolution stereographic photographs of hydrometeors, like those shown in sample images here, from three angles (as shown to the left), while simultaneously measuring their fallspeed. The cameras are triggered by a vertically stacked bank of sensitive IR motions sensors designed to filter out slow variations in ambient light. Fallspeed is derived from successive triggers along the fallpath.  The instrument is sensitive to snowflake sizes ranging from 100 micrometers to 10 cm (100,000 micrometers).

The above are some statistics from the first ever day of MASC field measurements in April 2011, taken at 8500’ altitude in the Wasatch Front.

The instrument is robust to cold and weather and runs unattended. Calibration is limited to occasional and straightforward camera alignment and lens focusing using a calibration tool that attaches to the instrument.

C and Python executables are available for image and fallspeed acquisition on PC platforms and for creating a live internet feed from the installation site. The executables include lossless (png) image compression to facilitate with data management. Tens of thousands of images might be obtained in a single day. Matlab and Python scripts are available for detailed post-processing.

The Multi-angle Snowflake Cameras was developed in the Department of Atmospheric Sciences at the University of Utah with support from the US Army, NASA, and the National Science Foundation.  

For more information, please contact at Particle Flux Analytics, or see

Garrett, T. J., C. Fallgatter, K. Shkurko, and D. Howlett, 2012: Fallspeed measurement and high-resolution multi-angle photography of hydrometeors in freefall. Atmos. Meas. Tech., 5, 2625-2633, doi:10.5194/amt-5-2625-2012