"Brian Case" wrote in message
om...
On the other hand I can't tell you how many times(numerous) I
intercepted a dust devil at 1000-1500 AGL and climbed out at less then
1kt or even did not climb. Most times however I get 3-6 kts out of
them. I have see dust devils go to 7-8000 feet up. Hate to tell the
one gentleman this that wouldn't fly into a dust devil, but if he flys
using thermals he is just flying into dustless dust devils, As far as
I can tell the only difference is if it is lifting air over an area
were it can pick dust up or not.

We are apparently sharing different definitions of "dust devils." The
ones that rage across the part of the country I fly mostly do not fit the
structure of a thermal.
Thermals, at least where I am, are rising volumes of air created by
differential temperatures on the surface. One of our best local thermal
engines is the black paved surface of Runway 10/28 at IYK. The equipment
parking lot for the highway maintenance yard is another. The location of
these is pretty constant and reasonably predictable and reasonably benign.
Dust devils on the other hand, while they may begin at convective
sources, are cyclonic whirlwinds that travel laterally across the ground,
sometimes for miles. DDs in our area are typically less than five meters in
diameter. One monster dust devil that went across a portable weather station
at the Naval Air Warfare Center spun the anemometer over 80 knots before it
ripped the mast apart. We watched that one travel about ten miles. On
another occasion, a monster went across a mobile home park and took the roof
off a home and dissassembled tool sheds like card houses.