Khan, Azmat Hayat*
On 28th March, 2001 (1530LT), a tornado produced surface winds greater than
65 kts in Chak Misran village near Bhalwal area.
This storm was much stronger-appearing on radar compared to a sqall-line of intense storms during late winter season.
This paper documents the structure of this storm, as reflected by charts and
visualized by satellite data.
March is the peak month of spring season and
sufficient isolation towards end of month combined with polar continental air
over upper parts of country results high degree of instability and produce
Satellite picture of 04 Z
& pressure pattern at 0600z on 28th March, 2001
On 28th March, at 0500PST,
continental air was penetrating into northern half of country. Also there was
sufficient moisture influx from Arabian
Right from surface to 18000 ft, charts depicted some what intense circulation over
central Punjab with centre near Sargodha area that acted as a vortex of southwest relatively
warm-moist currents and cold continental air from north-northwest.
850 mb pressure
pattern at 0500PST
on 28th March, 2001
Consequently a squall line of thunderstorms
developed. A number of stations in north Punjab
and upper NWFP including Lahore, Sargodha, Rawalpindi , Peshawar reported thundershowers in METARS.
The vortex formation was further accentuated
as the day progressed and moist atmosphere absorbed maximum energy.
Vortex formation further
intensified during afternoon as is evident from the 1200Z chart at 850 mb & satellite imagery of 0900Z.
850 mb analysis at 12Z
Satellite imagery at 09Z- 28/3/01
500mb analysis at 00Z on 28/3/01
Classification of 28th march Storm:
per eyewitnesses reports, wind storm associated
with hailstorm started at 1525 PST. Within next five minutes, cloud-base
seemed to touch the ground and destructed building structure, very heavy
equipment and uprooted steel electric poles.
electric poles were found imbedded half their length into the ground quite
far from their original locations. This reflects that poles were carried
aloft quite high.
pattern of destruction on ground suggest that the severe effects of winds
were initially from east/southeast towards west/northwest and then from
west towards east/southeast. It suggest the
whirling of storm/development of pressure
notice the rotary damage pattern of machinary.
Wind whirl pulled up heavy equipment like tractor trolleys and wheat
thrasher in a pattern showing the spinning motion of the air and thrown
far away from their original locations.
of 10 lives with human and animal dead bodies & their dismembered
parts dispersed quite far off. Also injuries to more than 100 persons due
to flying debris. It is somewhat a clear indicator that this destruction
was an outcome of tornado.
number of building structures and equipment in the vicinity of affected area, remained intact.
File photo of heavy equipment like
tractor trolley and wheat thrasher that were thrown far away by the suction
vortex/tornado on 28th March, 2001
Tornadoes come from the energy released in a
thunderstorm. What makes them dangerous is that their energy is concentrated in
a small area, perhaps only few hundred yards across.
They occur mostly during the spring and summer. They usually occur during the
late afternoon and early evening.
The size of area affected by the storm and
damage pattern on 28th March, 2001 in Chak Misran
suggest that strong convergence of winds(tornado)
caused the instantaneous destruction in the village.
* Author of this article is
Meteorologist in Pakistan Meteorological Department engauged
in operational research.