Now that we are officially into Spring the snow is starting to melt. Yes, some places might not have any snow, but many places at this time are seeing catastrophic flooding from a surge of warm air and near record breaking snow levels from this winter in the Mid-West.

But all of that flooding is from melted snow above 32 degrees with the addition of heavy rainfall.

But if you’re driving along a road and notice that the pavement is wet and it’s 24 degrees out, you might wonder why? Because you know it’s below freezing so how is the snow melting?

And science says you can have sub-freezing temperatures and see snow and ice melt.

As the sun’s rays beam down on Earth some of the solar radiation is absorbed by the atmosphere, but not much. And the Earth is a much better at absorbing. Meaning…

This can heat up the Earth to the magic temperature of 32 degrees and melt snow.

Snow and ice itself can be warmed to a higher temperature because of its albedo (the measure of heat absorption).

Surrounding objects, such as a tree, also take in heat absorption and can also reflect off heat. Meaning the tree surrounding the snow can melt nearby.

As an example, you look around a field and notice that there’s snow everywhere, but by the trees there’s nothing. It has to do with the warmth reflected off of a tree or a surrounding object and reaching a temperature warm enough to melt the snow.

It all has to do with heat absorption provided by the sun in order to melt snow below 32 degrees.

Evaporation also plays a role in how much snow can melt when it’s chilly outside. And on a windy day it can enhance the evaporation even more.

Advertisements