On 4/7/2016 6:26 PM, son_of_flubber wrote:
Mulling over a wave flight from last October and realized that I'd gotten
it into my head (perhaps erroneously) that the up (lift) side of rotor is
usually closer to the upwind ridge than the down side (sink) of the rotor.
So for example, if I persist in heading closer towards the slope/ridge
while in the downside of rotor, that I have a good chance of hitting the up
side (lift) of the rotor. In other words, the sink side of the rotor is
farther away from the upwind ridge than the lift side.

That's certainly true along the Front Range of the Rockies in the Boulder, CO,
area.

Atmospheric waves can only exist downwind of the obstruction generating
them...though (IMO) their relationship to geography beneath and downwind of
the generating obstruction doesn't lend itself to accurate, simple,
declarative statements. Atmospheric dynamics along "the Boulder part" of the
Front Range are such that only once did I ever attempt (unsuccessfully; my
wallet gave out) or even need to tow directly into a wave; every other time
has come via thermalling, sometimes in what seemed to be "aligned thermic lift
bands" paralleling the suspected/sometimes-visible wave, other times using
what was unarguably rotor.

Snip...
But what about my assumption that the lift side of the rotor is generally
found between the sink side of the rotor and the upwind ridge? Or does
this depend on the particular ridge and the particular day?

I'll be surprised (shocked?) if anyone can point to a rotor that ever lies
UPwind of the wave-generating geographic feature, if that's what you're
wondering about, though that's not to say "your wave" is the first along the
wind's streamlines. If there's genyoowine rotor upwind of "your wave
generating feature" it's coming from another, upstream, feature. FWIW, in the
absence of an upstream wave, don't assume the lower level winds on the upwind
side of the wave-generating feature will be "ridge-lift smooth"...reality
always rules!


And what about a downwind ridge? I've got it into my head that the sink
side of the rotor is between the lift side of the rotor and the downwind
ridge. There may be a band of ridge lift between the sink side of the rotor
and the downwind ridge. Are rules of thumb possible/useful or is this just
my limited experience on my local ridges?


I'm all ears on this question!

Bob W.