Earlier in the month, we looked at the chances of a white Christmas. In recent days, the odds have reduced, and the chances are looking more favourable that we will have snow, but what exactly is this cold, white stuff that everyone associates with Christmas?
Snow is formed when tiny ice crystals are produced from supercooled water droplets in clouds and stick together to create flakes. When they become heavy enough, they will fall to the ground.
If the air temperature is slightly above 0 °C as the flakes fall, the edges will melt and cause them to stick together. If snowflakes fall through cold, crisp air, they produce powdery snow that doesn’t stick together.
Each snowflake is unique and form hexagonal shapes as the most efficient arrangement of the water molecules in the flakes, but the are not actually white: they are translucent.
I still have my fingers firmly crossed that we are going to have some snow over Christmas and I’ll be watching the forecasts with interest.
Until next time, keep calm and apply some Science!