From AMS Glossary
A strong cold northeasterly wind blowing down into the Eden valley from the western slope of the Crossfell Range (893 m or 2930 ft) in northern England.
Beyond the stormy northeasterly flow, there is a belt of calm on either side of which may be a light westerly wind. The helm wind occurs when the general direction of the wind is between north-northeast and east. A line of cloud (the helm) forms along the crest of the ridge, and above the calm belt a narrow, nearly stationary roll of cloud (the helm bar) rotates about a horizontal axis parallel to the helm bar. It may occur in any month but is most frequent in winter and spring.