How do snowflakes form?

How do snowflakes form?

A snowflake begins to form when a water droplet freezes onto a pollen or dust particle in the sky. This creates an ice crystal. As the crystal falls to the ground, water vapour freezes onto the “primary” crystal, building new crystals which become the six arms of a snowflake.

Why are snowflakes symmetrical?

The ice crystals that make up snowflakes are symmetrical (or patterned) because they reflect the internal order of the crystal’s water molecules as they arrange themselves in predetermined spaces (known as “crystallization”) to form a six-sided snowflake.

Thanks to Virginia Poltrack for use of this photo
What determines the shape of a snowflake?

Ultimately, it is the temperature at which a crystal forms (and to a lesser extent the humidity of the air), that determines the basic shape of the ice crystal. Thus, we see long needle-like crystals at -5°C (23°F) and very flat plate-like crystals at -15°C (5°F).

The intricate shape of a single arm of a snowflake is determined by the atmospheric conditions experienced by the entire ice crystal as it falls. A crystal might begin to grow arms in one manner, and then minutes or even seconds later, slight changes in the surrounding temperature or humidity causes the crystal to grow in another way. Although the six-sided shape is always maintained, the ice crystal (and its six arms) may branch off in new directions. Because each arm experiences the same atmospheric conditions, the arms look identical.

Are snowflakes all unique?

As alluded to above, the randomness of the freezing process as snowflakes form leads to their unique shapes. Individual snowflakes all follow slightly different paths from the sky to the ground, and thus encounter slightly different atmospheric conditions along the way. Therefore, they all tend to look unique, resembling everything from prisms and needles to the familiar lacy pattern.

Here’s a video explaining the process more.

How do I take photos of snowflakes?

The temperature needs to be around -10°C as mentioned above, to get the large well developed flakes and so they don’t melt after settling. Here’s a video on snowflake photography, there are lots more on YouTube

Have fun in the snow. If you take any photos, be sure and share them with me on social media.

Original article by NOAA