How is clear air turbulence (CAT), unlike normal ones so dangerous for airliners, how does it ocurr ?

Question

How is clear air turbulence (CAT), unlike normal ones so dangerous for airliners, how does it ocurr ?

Answer 1

CAT is usually associated with jet streams and varies in intensity depending on where it is in relation to the jet stream.  The article below explains it in detail.

Non CAT is usually terrain induced (mountains, canyons etc,) or weather related (convection, low level winds etc)

you can locate the jet streams on water vapor satelite images, which will then give you an idea where to expect CAT

Answer 2

CAT is undetectable because it happens in clear air.  It is surprising when it is encountered.

Convective turbulence happens in clouds, so it is easy to predict.  We can slow down to Vb, turn the seatbelt signs on, make an announcement, or preferably, just fly around it.

CAT essentially happens when there is a change in wind speed or direction greater than a certain threshold over a short distance.  Air creates friction against other air and it all gets stirred up.  It can be very violent and it is more dangerous precisely because it is not visible.

Answer 3

While CAT is complicated, the real reason that it is dangerous is that it is difficult to detect because it is not associated with weather.  If there is no water vapor associated with it, radar won't detect it.  You can climb over or fly around weather.  The reason that CAT hurts people is that they're wandering around the cabin.

Answer 4

John is on the right track. CAT is undetectable and therefore more dangerous because you can't prepare for it. When turbulence is anticipated the pilot will make an announcement for you to remain seated and buckle up. With CAT you get no warning.

Answer 5

you know what, i have a book about CAT, which has about 100 pages only on this topic and how they are created, so it's a little complicated to describe it hier in brief.