[BC] 1310 The Ticket KTCK Dallas Towers

[Mike McCarthy]

Agreed....

A microburst (discovered by the late Dr. Fujita) is actually the 
opposite of a tornado.  It's the result of a large pool of rain and 
hail held aloft by inflow releasing and falling intensely to the 
ground in bulk.  Usually, rainfall in excess of 6"/hour occurs for a 
short period of time as a part of the microburst.  The rain/hail 
pulls the surrounding air to the ground at the same velocity as it 
falls.  It's reason why one feels a blast of cold air as hail falls.

The area involved is usually confined to less than 1/4 mile wide and 
radial in nature.  A downburst is typically a wider coverage event 
with less wind, but far more rain.  The  super heavy rain and wind 
coupled together in a downburst can create essentially the same 
damage as a microburst, but over a larger area.

The appearance of a well defined microburst or downburst from afar 
might resemble a tornado.  But with time, one would see the hazed 
area expanding away from the core.  Which is the #1 reason spotters 
are given to be patient and wait a few minutes on reporting anything 
which clearly doesn't have rotation or notable debris field.

Damage from a microburst can be catastrophic and as intense as EF-5 
winds due to compression when the winds reach the ground and have no 
where to go except outward.  The major difference in the damage mode 
is typically downward compression at the core of the downward column. 
Not lateral force winds except when close to the core.  As one moves 
away from the core, you will see a more linear damage mode associated 
with Derecho, Bow Echo, or other straight line winds modes as the 
winds fan out radially from the core.

Looking at the pictures and using shadows as a guide, it appears as 
if the winds were linear as the towers fell in the same direction and 
were more or less laid out parallel.  A twister would have flung 
stuff around a bit more and destroyed the associated ATU's.  Which 
appear to be untouched.

BTW...did anyone catch the various radar appearing domes  in the deep 
background.  If one is the local NWS radar, they should have a pretty 
good idea of what happened.

MM

At 09:40 AM 4/11/2008 -0400, Powell Way wrote

>A microburst IS NOT a mini tornado.  That said, a microburst or 
>other similar events can cause a lot of damage in a small area.