sycamore
Despite some differences in appearance to your cloud, I hope that the two important properties of the orographic cloud and the up-slope mist are apparent to you now:
firstly, how the phenomena would affect visual perception of range to the landmass;
and secondly, that both phenomena are fixed to the feature that gave rise to them - it was not that they were travelling in an area where IMC may develop at any time but rather that they had to avoid hitting a fixed fuzzy object that for some reason or other they had approached directly and at speed.