Snow

Snow forms when tiny ice crystals in clouds stick together to become snowflakes. If enough crystals stick together, they'll become heavy enough to fall to the ground. Snowflakes that descend through moist air that is slightly warmer than 0 °C will melt around the edges and stick together to produce big flakes. Snowflakes that fall through cold, dry air produce powdery snow that does not stick together. Snow is formed when temperatures are low and there is moisture in the atmosphere in the form of tiny ice crystals.