ASK THE METEOROLOGIST
“How does snow form from rain and then change back to snow?”
Emily Olin, Parkside Elementary
Most precipitation falls from a cloud in the form of snow initially. The temperature profile of our atmosphere is what determines what type of precipitation will reach the ground. If the whole atmosphere is near or below freezing, that snow will fall and reach the ground in the form of snow.
When it rains, the precipitation will leave the cloud in the form of snow before encountering temperatures that are above freezing closer the earth’s surface. At this point, the snow will melt to rain and fall to the ground as rain.
When the snow passes through a warmer layer before passing through another cold layer closer to the surface, it can melt to rain before refreezing back to snow if temperatures are cold enough. Depending on the temperatures and depth of these layers, precipitation types will differ.