Current monsoon rains likely to cause riverine flood

ISLAMABAD: The long-term temperature data shows a statistically significant increase of 0.014°C and 0.026°C per year in the monsoon and post-monsoon seasons, respectively.

The active period of monsoon for Pakistan is one-and-a-half month as compared to four months in India as it is situated in the western end of south-west monsoon area.

According to Pakistan Meteorological Department (PMD) the current monsoon rains are likely to cause riverine flood potential in main rivers of the country; high probability of urban flooding in metropolis cities; high probability of flash flooding in hill torrents of Punjab; positive impact on rice crop and negative impact on cotton crop; conducive environment for locust breeding in deserts; and sufficient water availability for irrigation and power sectors.

Majority of the PMD stations located at the south-eastern side exhibited an increase in rainfall while a decreasing trend in the north-western side of the northern monsoon belt of Pakistan was observed.

It is pertinent to mention here that 2.5 mm/day is the minimum amount of rain a day that labels it as a rainy day, while 4 mm/day threshold has been taken to depict a medium to high intensity rainfall events. The Northern monsoon belt of Pakistan receives more than 80 percent of the total rainfall in Pakistan.

A research study conducted by National University of Sciences and Technology (NUST) stated that there is a southward spatial shift in monsoon rainfall occurrence over Pakistan while an eastward shift in moderate to heavy monsoon rainfall events.

It said inter-annual variability is an important characteristic of monsoon in Pakistan, which makes it hard to predict a certain trend in rainfall pattern.

A more pronounced decrease is observed in monsoon rainfall as compared to the previous three decades, signifying a recent drier monsoon over the region after the anomalous heavy rains of 2010, it said.