The crippling effect of a concentrated deluge

livemint.com:

Mint report said the IMD had advised farmers to delay sowing key crops. According to government data, as of 14 July, area sown under rice was down 9.8% compared with last year. Sowing of pulses and oilseeds were down 16% and 10.4%, respectively, while that of coarse cereals was up by 16%.

As of 13 July, rainfall over North India was 75% above ‘normal’ rainfall for the period, that is the average from 1971 to 2020. While this implies that rainfall for the whole of July could be among the highest-ever recorded, this might not necessarily be the case. M.

Rajeevan, former secretary of the Ministry of Earth Sciences (under which the IMD falls), in an article in The Indian Express, noted that all seasonal rainfall in North India is concentrated within just 130-150 hours (not necessarily successive), with half the seasonal rainfall occurring in 30-40 hours. Thus, it’s possible that the current extreme spell could be followed by a dryer spell, lowering the total for the month as a whole. Nevertheless, it’s worth noting that, on average, well over 60% of the normal rainfall in July falls in the second half of the month.

Thus, even if the current month’s rainfall becomes more ‘normal’, it could still be one of the rainiest Julys in North India. Rainfall in North India in July since at least the 1990s has been much lower than in earlier decades. The spike in July in North India was sudden.

Rainfall for much of June was well below ‘normal’ for most of the region’s states, with the exception of Punjab. Himachal Pradesh, one of the states worst hit by the extreme rainfall, started the season in June with a deficit. By 5 July, it was registering a small overall surplus, of about 9%.