Just after February, the temperature starts rising in every part of the Indian subcontinent. The beginning of spring marks the emergence of flowers and the breeding season of animals. We the people of Manipur used the term ‘Phairen Thagi angaoba Leichil’ which is associated with love, trust, youth and growth. Positively, spring is the result of warm weather. During spring, heat waves and humidity started throughout the day and night.
This result leads to the warming of the earth atmosphere. Basically, the intensity of downpours is possible with the rising temperature. At this stage, the rains slowly start which marks the commencement of ‘Pre-monsoon’ season in the country. As per the India Meteorological Department, the pre-monsoon starts from the month of March tillup to May. Any rainfall in this period can be attributed as pre-monsoon showers.
The pre monsoon is known by the name Kal-Baisakhi in West Bengal, Mango Showers in Karnataka and Blossom Shower in Kerala. Generally, the rainfall is known by the name ‘April Rains’. Some studies suggest the early ripening of mangoes to pre monsoon rains and often referred as 'Mango Showers'.
More or less, pre monsoon season contributes to 21% rains in the North eastern parts of India. Almost 22 to 25% of the annual rainfall occurs during the pre-monsoon over different parts of the region. This is primarily due to the favorable location of the region with respect to the southernly winds from the adjoining Bay of Bengal and the prevalence of connective instability of the sub-tropical westerly jet stream and mid troposphere westerlies.
At present, all India pre monsoon rainfall (PMR) shows epochal changes. The change is closely associated with the global warming. In fact, the pre monsoon rains is attributed to the cyclonic circulation prevailing over Sub-Himalayan, West Bengal and Sikkim regions. In comparison, the co-efficient of variability of pre monsoon season is twice the value of the monsoon season rainfall.
Even before the onset of monsoon season, the pre monsoon (MAM) rain starts flooding in many parts of Manipur as studies defined. The pre monsoon flood events of 2014 (May), 2016 (May) and 2017 (May) was of severe type. The continuous rainfall of 2016 (May) led to raised water level in major rivers in valley areas.
The breaching of Imphal River at Kyamgei Muslim Oinam Loukon, sweeping away many houses and inundating thousands of pari of paddy fields. The strong current of flood water washed away the wooden bridge built over the Sengmai River, which connects Kakching Wairi Senapati Leikai, Kakching Chumnang and Phousupat Leikai. The other bridge carried away by the flood water connects Kakching Chumnang and Kakching Wairi Thongam Leikai.
The heavy rainfall also led overflow of water from Wangjing River, inundating six residential houses at Sangai Yumpham Part II Pulleipokpi Salam Macha. Many paddy fields in the area have been submerged in water.
ANALYSIS OF RAINFALL DATA DURING THE PRE-MONSOON PERIOD
|
Season |
2018
2019
2020
2021
2022
Pre-Monsoon
411.70
167.18
283.78
211.31
419.31
(Source- Directorate of Environment and Climate Change)
According to the report of Intergovernmental Panel on Climate Change (IPCC 2007), extremes wet climate is projected to become more severe in many areas whereas mean precipitation is expected to increase and dry extremes are projected to become more severe in areas where mean precipitation is projected to decrease. As a result, more flooding is seen in most tropical areas and Asian monsoon region.
The pre monsoon (MAM) flood is generally of short duration but high intensity rainfall during the period. Review literature suggests that the relationship between the amount of rainfall and flood response in a catchment is difficult to study. Antecedent conditions determine the response to an input of rainfall, while the flood response is often controlled by where in the catchment the rain falls.Studies suggest that the relationship between the amount of rainfall and flood response in a catchment is difficult to study.
Therefore, the need of the hour is to study the sudden changes in extreme rainfall which is causing floods and landslide in the state. Analysis of frequency of rainy days, rain days and heavy rainfall days as well as one day extreme rainfall and return period analysis in order to observe the impact of climate change on extreme weather events and flood risk can also be studied at different levels.
It is also recommending that government should prioritize the effected livelihoods of the people by extending their support to the affected communities. Intensive research is needed to investigate to a full extent the climate change vulnerabilities particularly extreme weather events in the area. Local communities should be equipped with climate change knowledge and extension of climate technologies to offset the vulnerabilities with effective climate adaptation plans.
Monsoon rains can come at any time of the day. But pre-monsoon rains come only in the afternoon or in the evening. Apart from this, there is also a difference of wind in both the rains. Pre-monsoon rains are dust storms caused by gusty winds.
Pre-monsoon season is synonymous with heat and humidity with uncomfortable conditions throughout the day and night. However, fairly stronger winds bring down temperatures to a comfortable level during monsoon season.
