GretÄ— writes:

Because snowflakes are very fragile and melt fast, it is necessary to work outdoors. The microscope, glass, camera, even fingers – everything that comes near the crystals – has to be cold. Taking pictures outdoors is difficult because of lighting, so it is necessary to wait for a moment when there is enough light, it is snowing and the snowflakes form beautiful crystals.

The first time I took the pictures at Technarium, snow fell in clumpy grains instead of crystals:

Two days ago, though, the crystals were perfect! x40 magnification in all pictures.