Helm Wind

The Helm Wind is a named wind in Cumbria, England, a strong north-easterly wind which blows down the south-west slope of the Cross Fell escarpment. It is the only named wind in the British Isles, although many other mountain regions in Britain exhibit the same phenomenon when the weather conditions are favourable. It may take its name from the helmet or cap of cloud which forms above Cross Fell, known as the Helm Bar, since a line of clouds over the fells can predict and accompany a Helm. Research into the helm wind was carried out by Gordon Manley in the 1930s. He interpreted the phenomenon in hydrodynamic terms as a "standing wave" and "rotor", a model confirmed in 1939 by glider flights.