As they can be spotted from most of the routes I bike regularly I use those chimneys over the at the fibreboard factory as a guide to what way wind's blowing.
And, what strength too.
Today, the white smoke wasn't making it far out of the top of the stack before being whipped eastwards. That, combined with an icy hail shower that tried its best to strip the skin off my face a half hour later, made my mind up to cut my losses and head for home sharpish. I'd had enough 'fun' by that point.