Localised Katabatic Wind

[jack.h...@gmail.com]

I live at the bottom of a hill, some 40 metres lower than the top.

I had long suspected a local katabatic effect but this morning, at around sunrise, it was very noticeable.  It was flat calm, clear sky, and then the vegetation (small trees) began moving significantly.  Even the foliage of a potato plant was shaking (I don't specifically grow them, but old potatoes with 'eyes' are fun).  I would guess that the wind speed might have been 4 or 5 knots (2 to 2.5 metres/ second) and then, just as abruptly, the wind dropped off and calm returned.  A lesser katabatic wind occurred a few minutes later.  All then became calm and remains so.

Jack