Here’s a drawing I did a while back, en plein air, walking on the Brecon Beacons in winter with a sketchbook of black paper and a stick of white soft oil pastel. It was a very misty day, the fog hung heavily over the landscape and washed out the colour from the surroundings.
scribblah 
Or should I say oil pastels! It can certainly pass as a charcoal!
It’s conte crayon, I think, which seems to work a bit like a cross between the two 🙂
So lovely! I’m always grabbed by charcoal drawings.
I love mists and fogs