Frozen Snow and Sun

Wet snow came down yesterday evening in a stormy flurry, sticking to the trees on the windward side. Then the skies cleared and the temperature fell to a few degrees C below zero and all the wet snow froze HARD.
The sun came up the next morning and shone out of a blue sky all day but without heat, never thawing the icy snow.
In the last few minutes of the setting sun I took this picture showing those small but very tough lichens.
The trees are just outside the library and in the background is one of the university buildings.