Kathmandu, June 11
With another delayed monsoon this year, Nepal has witnessed 33 delayed monsoons out of 48 recorded so far.
The Department of Hydrology and Meteorology said only three monsoons have been recorded to be on time since 1865, and only 12 have been recorded to occur before the onset date of June 10.
Although the advent of monsoon season is subject to a certain degree of deviation from set dates, the issue of such a large number of delayed monsoons has become a matter of concern.
Director General of DHM Dr Risi Ram Sharma claimed that the consistently delayed monsoons are a result of global climate change.
“Climate change has led to disturbances in terrestrial, atmospheric, and aquatic system, and the monsoons are no exception,” he said, adding, “Global warming has caused the advent and end of monsoons to shift, reflecting the changes in our global climate.”
Existing data states that the years of 1971, 1994, and 2008 received regular monsoons while the years of 1969, 1976, 1978, 1991, 1993, 1995, 1996, 2000, 2001, 2004, 2006, and 2007 received monsoon prior to the normal date.
After the development of a forecasting system in Nepal in 1968, Nepal had set the monsoon onset date on June 10, and withdrawal date on September 23 each year.
The year 1982 witnessed the largest deviation ever recorded from the set date with monsoon beginning on June 27 that year instead of June 10.
The year 2013 saw the largest deviation from the set monsoon withdrawal period, ending that year on October 19 instead of September 23.
The data also says that so far, monsoon has ended 28 times after the set date, 17 times before it, and just two times on September 23 itself. The withdrawal date for 1980 was not recorded.
A research carried out by Meteorological Forecasting Division by observing monsoon trends from 1981 to 2010 says that the existing monsoon onset date has to be shifted by 5 days to June 15 to accommodate for the deviations.
DG at DHM Sharma said, “Our research shows the monsoon onset date should be pushed by 5 days. We will undertake another review of the onset dates of monsoon, taking into consideration monsoon dates from 1991 to 2020 in future.”
Sharma underscored the risk of climate change leading to recurring floods, melting of snow caps, prolonged droughts, heavy rainfall among others, which would directly hamper agriculture and livelihood and increase the numbers of climate change refugees every year.
Min Kumar Aryal, a meteorologist at MFD, told The Himalayan Times that it was necessary to conduct a research that reviews monsoon onset dates to set a more accurate date.
He added that the MFD was taking the issue seriously and conducting several researches on the matter.
In response to the review, former DG of DHM Mani Ratna Shakya also agreed that Nepal needs to have a revised onset date by consulting the international society.
The MFD has predicted that the monsoon season could take about a week to reach Nepal. Meteorologist at MFD Barun Paudel said westerly winds are still active throughout the country, and easterly winds must begin for monsoon to start, and that the monsoon system that developed in the Bay of Bengal has reached Kerala of India in June 8, a delay of eight days.
Paudel said, “It is reasonable to expect the monsoons to be delayed by a week, since it reached Kerala a week late,” adding, “The recent rains in the country are from the westerly winds, and not the monsoon system.”