FFF,
You can and do get several air masses that appear to be very close vertically, but are not. Wave normally forms in stable air masses (unless the wind speed is large enough).
As the wave system forms, a 10000' thick airmass will bend so that the top of it at a crest may be at 12000' and at a trough at 2000'. The bottom of the next airmass will now be at 2000' in the trough. The wavelength is typically only a few miles.
As the airmasses are stable, they don't mix. Hence the stacked up lenticulars much as Speedy suggested.
10 knot plus (1000' per min) climbs are regularly achieved - these are powerful systems. The rotor induced turbulence under a lenticular can be spectacular - often described as like being inside a wasing machine at maximum spin. Landing when this extends down to ground is interesting - no chance of a go around
