No deficit, but rainfall skewed
The state-wise rainfall distribution map for the past weeks shows a heavily skewed distribution of rain. While floods wreaked havoc in Karnataka and Maharashtra killing over a hundred people in the first week of August, states in the east, north-east and north-west recorded heavy deficiencies.Updated: Aug 12, 2019 13:00 IST
There is officially no deficiency in monsoon rain in the country, according to the India Meteorological Department (IMD). From a 33% deficiency at the end of June, the number has reduced to 0% as on August 10, even though the country recorded a heavily skewed distribution of rains.
The state-wise rainfall distribution map for the past weeks shows a heavily skewed distribution of rain. While floods wreaked havoc in Karnataka and Maharashtra killing over a hundred people in the first week of August, states in the east, north-east and north-west recorded heavy deficiencies. Eight states, mostly in central and peninsular India, at the same time recorded “large excess” of rainfall.
For instance, Maharashtra recorded 161% excess rainfall; Telangana 148%; Karnataka 128% and Gujarat recorded 112% excess monsoon rain, while on the other hand Delhi recorded a deficit of 43%, Tripura a shortage of 69%, Meghalaya 60%, while West Bengal and Jharkhand were short by 42%.
“There was large deficiency in Gujarat, Kerala, Marathwada regions in the last week of July and now they are seeing floods. Kerala covered its deficiency in the span of three days. This is unusual. We are seeing extremely heavy rains, often the entire season’s rain in a very short period. Distribution of monsoon rains cannot be homogenous so we are not surprised by the fact that some states are still deficient while others receive excess rains,” said AK Srivastava, head, climate change research division of IMD Pune.
Experts say this large variability in spatial distribution of monsoon happens once every few years but what’s worrying is that states, which were heavily deficient as of last week, ended up recording heavy rainfall in the past few days and ended up with either normal or excess rainfall.
Since June 1, a total of 19% of the country has received excess rains, 14% was in deficiency and 64% received “normal” rains. Experts said even in some states that received “normal” rains, there were large localised aberrations.
Data collated by private weather forecaster, Skymet, shows that Mahabaleshwar, Dahanu, Palghar in Maharashtra received as much as 400mm rain on certain days while Sangli, Satara, Kolhapur in Maharashtra, Belagavi in Karnataka, which are otherwise dry regions, received around 200mm rain in a single day in some days in August.
“This is extremely unusual. Also, these places have been receiving such heavy rain for 10 days that now they face floods. The situation is similar in parts of Saurashtra. We are also noticing that earlier when a low pressure area formed over Bay of Bengal it would move towards the eastern states — West Bengal, Bihar, Jharkhand etc but for the last six to seven years there is a change in course, (and) it moves towards central India now,” said Mahesh Palawat, VP, climate change and meteorology, Skymet Weather.
The ministry of earth sciences (MoES) said climate change has led to two distinct patterns emerging more frequently in recent years during monsoon. “The dry spells or days with little or no rain have increased while days with extremely heavy rains in a short period have also increased. We had forecast a normal monsoon this year, after a delay in onset and slow movement in the beginning, monsoon has been normal,” said M Rajeevan, secretary, MoES.
Meanwhile, latest data from the World Meteorological Organisation (WMO) has sounded alarm bells on the exacerbating impacts of climate change. June and July were the hottest months this year and the 2015 to 2019 period was the hottest on record globally. WMO in March estimated that extreme floods in Kerala last August has led to total economic losses of ~4.3 billion. It said that rainfall in Kerala in August last year was 96% above the long-term average, with weekly total for the weeks 9-15 and 16-22 August was 258% and 218% above average, respectively. The WMO cited the floods as an extreme weather event, which it said was a larger part of other global catastrophic events being caused by climate change.
According to IMD’s Sunday bulletin, rain intensity over Gujarat, Kerala and Karnataka is likely to reduce from Monday. A fresh low pressure area is likely to develop over northwest Bay of Bengal and the neighbouring region on August 12, which is likely to move northwestwards and become more marked subsequently. “Under its influence, heavy to very heavy rainfall at isolated places is likely over north Odisha, south Jharkhand, north Chhattisgarh and east Madhya Pradesh during August 12 to 14. Kerala is also likely to experience heavy to very rainfall at isolated places during the same period,” the bulletin said.