Final answer:
Upside-down snow refers to the condition where the snowpack has a higher temperature at the bottom layer, not a type of snow. Regular snow, however, is white, falls from the sky, accumulates on the ground, and melts with warmth.
Step-by-step explanation:
The characteristics of upside-down snow can often be misunderstood as it does not refer to a specific type of snow but a condition where the snowpack has a higher temperature at the bottom layer compared to the top. This could potentially happen due to various reasons such as ground heat. However, if we are referring to regular snow, it is indeed white in color, falls from the sky, accumulates on the ground, and melts when it comes in contact with warm surfaces.
Regular snow is formed from ice crystals and is the solid phase of water. When the air temperature is above 0°C, the snow will begin to melt as the heat is transferred from the air to the snow, though this process takes time due to the need for a significant amount of energy for the phase change to occur.