NER / HISTORY & CULTURE
TABLE OF CONTENTS
The naming of Meghalaya was not based upon a singular community within its boundaries or mythology – it was chosen by its indigenous hill communities based on what their land invoked within them.
The word “Meghalaya” was collectively chosen when Meghalaya was granted statehood in 1972. “Meghalaya” means “the abode of clouds.” The word “megh” means “cloud,” and “-alaya” means “abode” or “home.”
Today, on World Meteorological Day let’s look at why Meghalaya receives the highest annual average rainfall in the world. This year’s theme is “****2023: The Future of Weather, Climate and Water across Generations”**** – a theme apt for discussion in the case of Meghalaya.
DID YOU KNOW?
The unique geographical location of Meghalaya
The state of Meghalaya is situated in a unique location between the Himalayas in the north and the Bay of Bengal in the south. The Meghalaya Plateau, stretching over 300 kms, east to west, encompasses the Garo, Khasi and Jaintia hills. This Plateau has a varied topography, with different areas having varied elevation levels – The Garo Hills are known for their dense forests, steep slopes, and scenic waterfalls. The Khasi Hills are characterized by their high peaks, deep gorges, and limestone caves, and are also home to the city of Shillong, which is the capital of Meghalaya.
Because of the distinct topography of these hills and plateaus, the rainfall distribution within the 22, 429 Sq.Km area is extremely varied and distributed.
In addition to this, Meghalaya falls within the Inter-Tropical Convergence Zone (ITCZ), which is an area near the equator where the northeast and southeast trade winds meet, resulting in a convergence of moist air and the formation of low-pressure zones. This convergence of air masses leads to high levels of atmospheric instability, which in turn results in frequent and intense rainfall, especially during the monsoon summer months.
The region, thus, is one of the wettest places on earth, with an average annual rainfall of around 11,777 mm, due to its proximity to the equator and the ocean, presence of mountainous terrain and unique geological formations.
The Southwest Monsoon winds encounter the hills, valleys and gorges of Meghalaya
The southwest monsoon winds originate from the Indian Ocean and Arabian Sea, and as they move inland towards the Indian subcontinent. The mountains act as a barrier, forcing the winds to rise and cool, which leads to the formation of clouds and rainfall. As the southwest monsoon winds move further eastwards, they cross the plains of Bangladesh and bring rain to the northeastern states of India, including Meghalaya.
The monsoon winds are seasonal and typically begins in June and lasts until September or October, bringing heavy rainfall to the region during this time.
What is interesting is how these monsoon winds come in contact with the Garo, Khasi and Jaintia hills of Meghalaya. The high hills and plateaus of the region enhance rainfall by forcing the moist air to rise even further. In general, taller and steeper hills or mountains tend to produce more rainfall than smaller ones, as they force the air to rise higher and cool more quickly. The Khasi and Jaintia hills in Meghalaya are particularly effective in enhancing rainfall, as they rise up to 1,800 meters above sea level. These winds rise up the eastern and southern slopes of the Meghalaya plateau, leading to heavy rainfall on the windward side and relatively drier conditions on the leeward side.
Valleys and gorges, too, contribute to high rainfall in the region by funnelling and concentrating moist air, which can then be lifted and cooled, leading to the formation of clouds and precipitation.
This unique combination of the monsoon winds with the diverse terrain in the region help in creating different microclimates.
According to data from the Indian Meteorological Department, the average relative humidity in Meghalaya ranges from around 75% to 90% during the monsoon season from June to September. This high humidity, combined with the southwest monsoon winds and the topography of the region, contributes to the high rainfall in the region.
In Meghalaya, the humidity levels are generally high throughout the year, but they are particularly high during the monsoon season when rainfall is at its highest, which further increase the humidity levels in the state and dropping the overall temperature. The region, thus, is perpetually covered in fog, dew, mist and rain (from small spells to sudden thunderstorms) all around the year.
Meghalaya's lush dense forests contribute to high rainfall by facilitating evapotranspiration.
Evapotranspiration is the combined process of evaporation and transpiration, whereby water is transferred from the ground to the atmosphere through both evaporation from the soil and transpiration from plants. Transpiration occurs when plants absorb water through their roots and release it into the atmosphere through small pores in their leaves.
The dense vegetation and forest cover in Meghalaya act as a natural sponge, absorbing large amounts of water from the rainfall and soil. This absorbed water is then released back into the atmosphere through transpiration, which significantly increases the humidity levels in the region.
In addition to this, the water vapour released through evapotranspiration creates a cooling effect in the atmosphere, which can contribute to the formation of clouds and ultimately rainfall.
Climate change and Rainfall in Meghalaya
According to the Meghalaya State Climate Change Action Plan, climate change is set to increase uncertainties in weather patterns with rainier monsoons and drier winters.
Changes in monsoon season: Climate change has led to changes in the timing and duration of the monsoon season in Meghalaya. The monsoon season in the state has been shifting, with a delay in its onset and a shortening of its duration. The intensity of rainfall during the monsoon season has been increasing and all districts of Meghalaya is projected to receive even higher precipitation over the following years, especially in the Jaintia Hills.
Increase in extreme rainfall events: Climate change has led to an increase in extreme rainfall events in Meghalaya. According to data from the Meghalaya State Disaster Management Authority, the state has experienced several instances of heavy rainfall and flooding in recent years. For example, in 2018, Meghalaya experienced one of its worst floods in decades, with heavy rainfall causing landslides and flooding in several districts.
Decrease in the number of rainy days: Meghalaya has been experiencing a decline in the number of rainy days over the past few decades. According to data from the India Meteorological Department, the average number of rainy days per year in the state has decreased from around 160 days in the 1950s to around 130 days in the 2010s.
Changes to Forest Vegetation: future climate changes may make the area inadequate for existing vegetation types. This is a cause of great concern as the region is home to countless endemic flora and fauna species, many of which have been declared rare and endangered.
Meghalaya, due to the combination of topographical, meteorological and geographical factors, will continue to remain one of the regions with the highest rainfall in the world. The different microclimates have contributed to unique ecosystems – ecosystems that local communities fiercely protect and conserve. Community forests and community-conserved areas are great examples of this. The high number of endemic species in the region have led to increased recognition as biodiversity hotspots and have gained attention worldwide.
Today, thanks to this very rain, the state is attracting nature-lovers, birders, researchers and adventure enthusiasts from all around the world. Just last year, the state hosted kayakers from all over the world and the year before that, the first bioluminescent mushrooms in the country were discovered here.
If this attention and awareness continues to gain traction, the region will continue to be able to conduct further scientific research and also provide economic opportunities for locals through ecotourism and conservation efforts.