Rainfall pattern changing in India

Trend in monsoon rainfall from 1961 to 2004

Weather prediction and disaster response have become issues fuelling the blame game between state officials in Uttarakhand. An analysis of rainfall data for the past five years, available on the website of the India Meteorological Department, points to changes in rainfall trends in India, with a greater number of incidents of excess rain in Uttarakhand in June. The trends in rainfall do not indicate the kind of disastrous rainfall the state received this year, but it does point to the necessity for a robust disaster management programme, which as of now does not exist in the state.

The areas of Uttarakhand affected by the recent floods, particularly Uttarkashi, have experienced excess rains in June for the past several years. Last year, there was a rainfall deficit in the same month across the state. But data for the preceding five years indicates a trend towards excess rainfall in June.

In 2011, Uttarkashi received 146 per cent excess rainfall compared to the long period average (LPA). The corresponding figures for 2010, 2009 and 2008 are 26 per cent, 31 per cent and 98 per cent. Chamoli received 57 per cent excess rainfall in June in 2011, 18 per cent in 2010 and 59 per cent in 2008. Rudraprayag also received a deficit rainfall in 2008, 2009, 2010 and 2012, but the year 2011 witnessed excess rainfall of 70 per cent.

District-wise rainfall trends in Uttarakhand from 2008 to 2012
	Chamoli		Rudraprayag		Uttarkashi
	R/F*	% departure from LPA#	R/F*	% departure from LPA#	R/F*	% departure from LPA#
2008	163.8	59	148.9	-30	298.3	98
2009	32.2	-69	17.8	-92	197.3	31
2010	121.8	18	166.6	-21	189.9	26
2011	170.5	57	369.6	70	363.7	146
2012	41.1	-62	95.4	-56	45.6	-69
*Rainfall #Long Period Average

India receives more rain in May and June

Monsoon trends from 1961 to 2004 analysed by scientists show that the amount of rainfall received has increased in the months of May and June across India. In northwest India where Uttarakhand lies, this amount has increased by 22.4 per cent. The data also shows a decrease in rainfall in July and August. The northwest region receives 6.7 per cent less rain than before in these two months.

“June has more rainfall than before, while for July it is reducing. This change has to be acknowledged and the impacts should be studied,” says J Srinivasan, professor, Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru.  

 

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