Every winter at Stanwell, we talk about the Katabatic Wind (offshore wind) which seems to occur with regularity sometime in the afternoon between 2.30pm and sunset.
The Katabatic Wind is common in Alpine regions were cold air descends down mountain sides and into Valleys, (open the fridge door and feel the cold air descend onto your bare feet).
Our Stanwell Katabatic may be associated with this phenomenon to a degree due to a valley like setting but may have more to do with the “Land Breeze” which occurs in winter due to the land mass being cooler than the Sea. This is important to realize as an “offshore Breeze” can occur anywhere along the coast line, not only Stanwell with its Valley type configuration.
Flying at Stanwell on a winter afternoon should be flown with the expectation that a Katabatic may be establishing underneath you and with reduced height, you can suddenly find yourself going down quicker than you would like.
Often, the Katabatic can be observed with key clues such as the texture on the Lagoon, the direction the birds are landing, smoke drift from houses in the Park area. And observing how others are landing. Quite often, some waving and shouting by pilots on the hill and/or in the landing area should raise some alarm in you.
If you are caught in a Katabatic Wind, the worst place to fly is adjacent to the hill side as this is usually the strongest down draught, if you are clear of the “big hill” do not be tempted to fly along the small cliffs unless you can make the beach.
If you cannot make the beach, it is advisable to fly inland, you may finish up in the trees but you will stay airborne longer, and dry.
There is a Wind Sock near the Shute at Stanwell, but does not reveal the Katabatic as it is some what sheltered by the Dune. On many occasions, I place a home made sock near the edge of the Park, Ideal for letting you know when to do a Westerly approach into the Shute/Park.
Sydney Hang-gliding Club