Stealthy Lines and Excessive Colour

There's something wonderfully immediate about using charcoal that other mediums don't provide for me.  I like to draw big, at least big compared to a lot of my work which is around a4 - a3 in size.  I guess these are a2 or a1, I'm not sure, but they're certainly bigger than usual.  When doing this sort of thing I never mark things out first, I just draw straight on to the paper.  No room for mistakes here, which makes things quite challenging sometimes, especially - if like when I drew these - it was about minus 100 degrees.