[GoldCountryRedneck]

Primarily the wind direction and the lay of the land.

Thanks Thermal. Yours, and with the response from another FReeper, provided much in the way of de-mystifying (no pun!) the phenomena

I'll still give 'em wide leeway tho'...

I as I told cpd,I've considered glider training and have taken a few rides up in Napa. Thing is, there's no such thing as a 'missed approach'!

Thanks again!

[Thermalseeker]

Thing is, there's no such thing as a 'missed approach'!

That's why you have spoilers. They are "negative throttle". Your final approach in a glider will be considerably higher than a power plane. You use spoilers to kill the excess energy and altitude. You'll like 'em so much that you'll want 'em on everything you fly.

You'll really enjoy flying gliders and it'll make you a better, more coordinated pilot. It's also a good place to really, really learn about spins. Have fun!