… The sky is breaking through. Through swirling clouds, covering everything to the horizon, pouring continuous streams of water. Rain, not like a bucket, but like a thousand buckets, hits the roofs and crowns of trees. Due to water jets, visibility is not more than a dozen meters. From time to time, twilight is illuminated by bright flashes of lightning, thunder shakes everything around … It is hard to imagine that such weather can last several weeks.
This formidable phenomenon is monsoon rain. Dangerous and at the same time beautiful, as it became the basis of the life of the population of many countries. In the countries of South and Southeast Asia, the onset of monsoon rains await with hope and anxiety. Delayed wet season causes drought. And too intense rains lead to flooding. Both are fraught with adverse consequences.
How are monsoon rains formed?
Monsoon is a type of wind operating on the border of the ocean and a large land mass. Their main feature is seasonality, that is, they change direction depending on the time of year. Due to the varying degrees of heating and cooling of the continents and the surrounding waters, regions with different atmospheric pressures are formed. The baric gradient is the cause of the wind blowing in summer from the ocean to land, and vice versa in winter. The summer monsoon moves from the sea and brings moist air. Clouds arising from these water-saturated oceanic air masses become a source of monsoon rains.
Monsoon countries
The monsoon effect is most pronounced in the climate of the countries of South Asia: India, Pakistan, Bangladesh, Sri Lanka. For the first time, Europeans learned about these winds from Arab travelers. Therefore, the Arabic word "Mausim", meaning "season", somewhat modified in the French language, became the name for the monsoon.
Wet winds, bringing summer precipitation from the ocean, are characteristic of both East and Southeast Asia. China, Cambodia, Vietnam and other countries also owe agricultural development to monsoon rains.
The North American monsoon operating in the eastern United States also stands out. In Russia, the effect of seasonal winds is clearly manifested in the south of the Far East.
Monsoon rain - a long-awaited event
Residents of countries with a monsoon climate always await the arrival of summer rains, because the start of agricultural work depends on their timely onset. Soils dried up during the dry period are again saturated with moisture. Water reserves in rivers and lakes are replenished, large volumes are accumulated in reservoirs. This precious moisture is then used in the dry season to irrigate the fields.
The monsoon rainy season begins with joy and glee over the long-awaited freshness, the decline in heat, which lasted several months. Bright greens appear, many plants begin to bloom. This is the heyday of nature. The main thing is that the monsoon season begins on time. Then usually do without unpleasant surprises.
Rains are not only good
The monsoon rain that started in time is the hope of a good harvest. But often the amount of precipitation exceeds all norms. The result is that a joyful event turns into a natural disaster.
In September 2014, much was written about floods in India and Pakistan. The somewhat delayed wet season was marked by incessant monsoon rains for several days, which caused massive floods. The Ganges River and its tributaries overflowed, flooding the surrounding area, along with hundreds of villages. The number of victims reached several hundred.
Loose rocks saturated with water began to move down the slopes of hills and mountains that were not fixed by the forest. The result was hundreds of large and small landslides, exacerbating the scale of the disaster. Blurred and flooded roads made it difficult for rescuers to arrive and evacuate people from dangerous areas.
The reasons for the catastrophic consequences
Of course, monsoon rain of high intensity led to such adverse consequences. But there are several more reasons that are not directly related to precipitation. The first of them is that the majority of the population of these countries lives in the floodplains of large rivers, where there are more fertile soils and where it is easier to provide field irrigation during drought.
The second reason is deforestation of the slopes of the Himalayas, foothills and steep slopes of the Deccan plateau. The loose layer of plant litter located under the forests absorbs a lot of moisture, seeping through it and replenishing groundwater reserves. In addition, tree roots hold together soil particles, preventing them from being drawn down a slope as part of landslide masses or mudflows.
The conclusion seems to be simple: stop deforestation on the slopes of the mountains and take measures to restore the vegetation cover. But in countries where most rural residents can use only firewood as fuel for cooking and heating homes during the cold season, the ban on cutting trees will cause new problems.
