India rains: 41% more rainfall from October 1-21 in country, Uttarakhand records 5 times higher rain: IMD
Mumbai, Oct 21: India received 41 percent more rainfall than normal from October 1-21 with Uttarakhand alone recording more than five times its normal precipitation, IMD data showed on Thursday.
Providing a numerical perspective to the unusually heavy rains ravaging several parts of the country, particularly the hill state of Uttarakhand in the north and coastal Kerala in the south, the India Meteorological Department said the country received 84.8 mm against the normal 60.2 mm this month. Of the 694 districts in the country, 45 percent (311 districts in 16 states and union territories) recorded rainfall in "large excess" and 14 percent (96 districts in six states and UTs).
Uttarakhand, where rains have claimed the lives of more than 54 people, recorded 192.6 mm against the usual 35.3 mm from October 1-20. The monsoon has wrought huge damage in the state, triggering floods and landslides that have blocked highways and smaller, key roads. Figures for the state were available till Wednesday, October 20.
Kerala received 445.1 mm of rainfall until October 20 as against the usual 303.4 mm. More than 40 people have been killed in Kerala, where videos of a house being swallowed by a swollen stream and landslides give a sense of how brutal the lashing was. Heavy rains have also hit Sikkim, sub-Himalayan West Bengal and Uttar Pradesh, displacing people and damaging property.
Experts attribute extreme weather events to various causes, including warming of the seas, unabated development, and delayed withdrawal of the monsoon. Balaji Narsimhan, professor at the Civil Engineering department, IIT-Madras, said it was undoubtedly an "unusual October" and pointed to "infrastructural challenges and unabated development".
"Many
of
these
extreme
weather
events
have
taken
place
earlier.
But
now
places
are
more
densely
populated
which
amplifies
the
impact,"
Narasimhan,
who
also
studied
the
2015
Chennai
floods,
told
PTI.
In
December
2015,
Chennai
received
its
highest
rain
in
100
years
in
which
more
than
250
people
were
killed.
Discussing
the
situation
in
Kerala,
Narsimhan
said
the
state
gets
bountiful
rainfall
both
during
the
Southwest
monsoon
and
the
Northeast
monsoon
but
this
year
has
been
different.
Explaining
the
heavy
rainfall,
IMD
Director
General
Mrutunjay
Mohapatra
said
October
saw
the
formation
of
two
low
pressure
areas
(cyclonic
circulations
that
bring
in
rainfall
and
strong
winds).
In Uttarakhand, he explained, the interaction between western disturbance and the low-pressure area resulted in heavy rains this week. The western disturbance over north India is a phenomenon typically observed in non-monsoon seasons.
"The interaction of cold winds of western disturbance and the warm winds of the low-pressure area bring in thunderstorms and heavy rainfall," Mohapatra said, adding that such interaction had taken place during the deadly deluge in Uttarakhand in 2013 in which hundreds of people were killed. M Rajeevan, former Ministry of Earth Sciences secretary who has been studying the Southwest monsoon for more than three decades, said there is a delayed withdrawal of the monsoon. Since the retreat has been late over the last few years, the IMD in 2020 had revised the withdrawal date from northwest India.
This year, the withdrawal of the Southwest monsoon from northwest India commenced on October 6, the second-most delayed withdrawal since 1975. In 2019, it had started on October 9.
The IMD said its complete withdrawal from the country is expected around October 26. "More importantly, the active conditions of Southwest monsoon which began in September have still not ended. Usually, such an active phase does not last for a month, but this time it has," Rajeevan said. Warming of seas around India is another factor, Rajeevan pointed out.
He said the warming of the Bay of Bengal and Arabian Sea helps in forming a cyclonic circulation. This year, it is aided by La Nina conditions - the phenomenon is associated with the cooling of the Pacific waters and usually results in good rainfall activity - and some remnants of cyclonic circulation from the Pacific Ocean.
Once these remnants enter the Bay of Bengal, the warm water aids in formation of cyclonic circulations. In a paper published earlier this year, Rajeevan along with other meteorologists, said from 1970 to 2019, 7,063 extreme weather events killed 1,41,308 people in the country. PTI