Rotor and mechanical turbulence are close cousins. Rotor is the
rotational swirl that forms downwind of certain shapes,
usually a persistent, strong rotational flow. Mechanical turbulence is a more random
stirring of the air downwind of obstructions.
The distinction is of little use for us because we don't typically
fly near hills but, knowing the difference can be helpful since the shape of
obstructions is important. Those that lend themselves to rotor are particularly
dangerous since they can leave a fairly steady wind that's lulls a pilot into launching
into what is actually a
rotor.
Watch this video to get an idea of how bad that can go. This is a
good tool to help visualize what the air may be doing and hopefully to
beg off conditions that would be rib-cracking or worse.
If you fly in mountainous areas then this video should really hit home,
especially if you're visiting the area and aren't familiar with local
idiosyncrasies.
There's no amount of skill that can prepare a pilot for the worst of
what mother nature can dole out. Like the cyber-villain in "War Games,"
who said after nuclear holocaust was barely averted: "the only good move is
not to play."
Go
here for information on dealing with turbulence and collapses.
Sometimes it's just best not to mess with mom. She's
got some nasty surprises up her sleeve. After getting thwacked while
kiting on a seemingly innocuous winter mid-day, I'll attest to the
wisdom personally.
