UP, Rajasthan dust storms set off by cyclonic circulation in Haryana
The deadly dust storm that swept parts of Rajasthan and Uttar Pradesh which left over 100 dead was due to a cyclonic circulation over Haryana, weather experts said. The experts also estimated the wind speed during to the storm may have gone up to 100 kilometres per hour.
The
winds
were
so
violent
that
a
number
of
houses
collapsed
and
electricity
poles
and
trees
got
uprooted,
as
the
severe
dust
storm
swept
parts
of
these
states.
The
phenomenon
was
restricted
to
these
two
states,
largely
because
of
external
and
domestic
reasons,
experts
said.
There were primarily four reasons that lead to the thunderstorm -- excessive heating, availability of moisture, instability in the atmosphere and a trigger for the storm, India Meteorological Department (IMD) Additional Director General Mritunjay Mohapatra said.
"The
northern
plains
have
been
witnessing
temperatures
of
over
40
degree
Celsius.
There
were
two
sources
of
moisture
--a
western
disturbance
over
north
Pakistan
and
adjoining
Jammu
and
Kashmir
and
easterly
winds
from
the
Bay
of
Bengal,"
Mohapatra
said.
The
cold
winds
from
the
western
disturbance
were
making
atmosphere
unstable.
"The trigger was a cyclonic circulation over Haryana," Mohapatra said.
This led to the formation of two cloud patches, said Mahesh Palawat, Vice President (Meteorology and Climate Change) of Skymet, a private firm that provides weather forecast
One patch moved to north of Delhi, while another patch moved over the Alwar, Agra, and Dholpur belt, which was more deadly.
Mohapatra said it was difficult to record the wind speed as the phenomenon was restricted to only small patches. In Delhi, where a milder version of the dust storm and thunderstorm struck, the wind speed was recorded as 69 kmph.
However,
Palawat
estimated
that
the
wind
speed
would
have
been
more
than
100
kmph.
Laxman
Singh
Rathore,
former
Director
General
of
the
IMD,
said
wind
speed
is
normally
around
50
kmph
in
a
thunderstorm.
"In case of a dust storm, due to excessive heating, the water from the clouds evaporates before it could land. So soil is dry and the severe winds lift up this soil up to 500 metres above the land.
"The wind speed can rise up to 100 kmph and in some case, it can reach 130 kmph making conditions severe," Rathore, who is also a member of the National Disaster Managment Authority, said.