"Morgans" wrote in message
...

"Mike Rapoport" wrote in message
.net...
Rotors do not extend much above the ridgetops. The waves themselves are
smooth until reaching the tropopause except the extreme case of breaking
waves.

Before Mike, Jim in NC wrote:

The waves extend way up past the peaks, and so do rotors.

I guess it depends on your definition of "way past". As per my other
quoted
post, about destructive part of the rotor going to 2 thousand over the
ridge, I think that is way over. Plus, I want to be well above where the
rotor is still destructive, like another couple thousand. That is really
way past to me. YMMV

I just want people to know that if they are thinking of going over a pass
with only a couple thousand to spare, if the wind is blowing just right,
they could be in big trouble, whether they see it or not. Right?
--
Jim in NC


Rotors can't extend much past ridgetop level because they are formed from
the low pressure produced on the downwind side of the ridge. My
observations from living and flying in one of the best places to see and
observe mountain wave systems is that the rotor seldom extends above the
ridge more than a few hundred feet. There are a lot of pilots who attribute
any turbulence in the mountains to "rotors" but a rotor is a specific
condition where there is closed circulation, looking very much like the
Bonzai Pipeline in Hawaii rolling over but not moving forward. At Minden,
virtually nobody flys when there is enough wind to produce a wave system
with a rotor. Only the bravest towplane and glider pilots walk the tarmac
on those days....

When there is a *real* rotor, the towplane and the glider sometimes find
themselves facing each other head on!

Mike
MU-2