To      : All Emergency Management Agencies
      From    : Wireless Institute Civil Emergency Network
                Australia
      Information for inclusion in this fortnightly Bulletin
      should be sent by one of the following methods :-

      Postal  : WICEN, P.O. Box 106, Mitcham, Victoria, 3132
      InterNet: vk3tp@csource.oz.au
      FidoNet : Paul Walton @ 3:632/404
      Packet  : vk3ur@vk3bbs.vic.aus.oc
      Voice   : Paul Walton (03) 754-8646 (A.H)

WICEN.051                     STORM WATCH                  19/6/94


       Following  the severe  wind and  hailstorms in the Northern Rivers
Region in November, 1992, Leith VK2EA and Norm  VK2BBY both joined the  Severe 
Storm  Watch  Volunteers, set  up  by the Met. Bureau. As  little  guidance 
was  available  on what  to do, they started experimenting on detecting and
tracking  thunderstorms  by radio as well as by visual means.

       Equipment was, and still is, the simplest possible, so that any ordinary
mortal could do the same thing with  what they had on hand.  Although   better 
results  could  be  obtained  with  more sophisticated  equipment , they  are 
both  still  using  portable transistor  receivers  which are capable of tuning
down to 150kHz. It  was  found  that  these  sets, used  with  headphones can
give accurate bearings on isolated storm cells by nullifying the static that
they generate to determine the direction.

       As  a  thunderstorm cell builds it emits a peculiar "Hashy" radio  noise
 long  before  it starts  throwing lightning. Average storms  only  produce 
about  one  static  click per minute, but a rip-tearing one may generate
several hundred per minute, and is an indication of the storms  intensity. Of
course the listener has to learn to  disregard all  the "DX" static and other
generators like electric fences and other appliances.

       Norm and Leith are some 70km apart and thus have sufficient separation
to allow accurate  cross  bearings to be taken. So  far they have successfully
tracked nearly  every storm that has passed within 300km  from Norm's home 
(Palmers Island, near Grafton) and 100km from Leith VK2EA's home
(Goonellabah,near Lismore).

       On  November 20, 1993  a severe storm hit the small town of Tucabia
which is near Grafton. Of  the  approx. 100 houses in  the area, some 70 lost
or had  significant  damage to  their roofs. At least  3  buildings were 
totally  destroyed  (including the local bushfire brigade shed). Norm and Leith
recorded their observations that afternoon.

       The storm cell that hit Tucabia was only one of a number of cells that
developed during that  afternoon and  evening. Most  of the cells were  trying
to  build on a  hot day  (36 deg) against a Northerly wind. The one that hit
Tucabia was a storm that built up from the moist and  lifting air in a strong
South Easterly change. From Lismore (over 100 km away) the cloud was  described
by  Leith VK2EA as a "Tall pillar  of  dark  cloud, standing  vertically and
back-lit by incessant and intense lightning. Static clicks [on the radio] too 
numerous  to count - estimated  at several hundred per minute". Norm VK2BBY
stated that "At no stage in the afternoon was there any sign of a severe cell
building up. The  indications were that  cells  were  only  local  and that 
there  was  insufficient moisture  in  the  atmosphere  for  sustained  cell 
build  up " . The building of this severe storm was very rapid.

       Amateur radio is a perfect vehicle for  Severe Storm Watch. Plenty of
observers  over  the  coutryside, instant communications and  lots  of 
expertise. Leith, Norm  and  other Amateurs  in the Northern Rivers  area also 
send reports of  severe storms  to the University of New England's Geography
and Planning Department, who are also interested in Severe Storms.

       If  anyone is  interested in Severe Storm Watching they can contact
Leith VK2EA at Fiford Ave, GOONELLABAH, 2480  or  on Phone 066-242550.

       Thanks  to  Leith Martin VK2EA and Norm Bodycote VK2BBY for the
information.

Greg Wilson, VK2DIL,
RCO Northern Rivers,
WICEN NSW