WW2010
University of Illinois

WW2010
 
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Online Guides
 
  introduction
 
> meteorology
 
  remote sensing
 
  reading maps
 
  projects, activities

Meteorology
 
  introduction
 
  air masses, fronts
 
  clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
  hydrologic cycle
 
  light, optics
 
  midlatitude cyclones
 
> severe storms
 
  weather forecasting

Severe Storms
 
  introduction
 
  dangers of t-storms
 
  types of t-storms
 
> tstorm components
 
  tornadoes
 
  modeling

Tstorm Components
 
  introduction
 
  updrafts/downdrafts
 
  wind shear
 
> outflow phenomena
 
  wall clouds

Outflow Phenomena
 
  introduction
 
  gust fronts
 
  microbursts
 
  scud clouds, virga
 
> rain foot, dust foot

User Interface
 
  graphics
> text

NOTE: We've guessed that you're not using a client that supports colored tables and have tried to compensate. Low graphics mode looks much better on clients that do... we recommend switching to Netscape 3.0 or Microsoft Internet Explorer.
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Rain Foot and Dust Foot
driven by microbursts

We are looking west at the south flank of a severe multicell storm that bordered on becoming a supercell at times. Some rotation and several wall clouds accompanied the bursts of large hail and microbursts with this southwest Texas storm.

[Image: initial spotting of rain foot (55K)]
Photograph by: Moller

A rain foot (below) was developing at this time, with rain-free base in the foreground and a small wall cloud southwest of the rain shaft.

[Image: developing rain foot (56K)]
Photograph by: Moller

Several minutes later the rain foot was beginning to curl up towards the wall cloud. Even from this distance of about 10 miles, strong winds were evident from the motions of the laterally spreading precipitation.

[Image: rain foot curls (51K)]
Photograph by: Moller

This seems to verify that a microburst is occurring, and also that many wall clouds likely result from an injection of rain-cooled air into the severe storm updraft.

[Image: has appearance of a tornado (54K)]
Photograph by: Moller

This is not a tornado, but a microburst with precipitation being pulled into the wall cloud and updraft of the multicell storm.

[Image: dust foot (57K)]
Photograph by: Moller

Similar to the rain foot is a "dust foot," seen here spreading and curling upwards from left to right. An aircraft engaged in low-level operations should not venture into these rain or dust feet! Spotters should check out the area that has been affected (if possible) for any sign of damage. This was a multicell storm that also produced heavy rain and small hail.



scud clouds, virga
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.

Wall Clouds