Tropical cyclone Gaja recently caused the deaths of at least 33 people in the southern India state of Tamil Nadu. Gaja's high wind and heavy rains caused landslides and building collapses. Gaja's maximum sustained winds had reached about 75kts (86 mph) when it hit southern India on Friday November 16, 2018. This meant that Gaja was the equivalent of a category one on the Saffir-Simpson hurricane wind scale. Today another tropical low is also moving over southern India and is expected to produce more heavy rainfall in the same area.
The summer monsoon is a regular feature this time of year in India, and it can bring heavy rains to the region. However, periodically areas of low pressure can form within the general monsoon trough and bring even more rain.
India's southwest monsoon (summer rainy season) normally occurs between June and September. This year's monsoon has been assessed as average but India's Meteorological Department statistics show that daily mean rainfall for the country has recently been above normal. At least 15 people were killed by floods and landslides in India on Wednesday July 11, 2018. So far this year, close to 200 deaths may have resulted from India's heavy monsoon rainfall.
In the past couple weeks rainfall has had a significant impact on Sri Lanka, southwestern India, Bangladesh and eastern India. Monsoon rainfall caused widespread flooding, devastating mudslides and displacements of many thousands of people in Sri Lanka. Over 200 people's deaths have now been attributed to this disaster. Then cyclone Mora formed in the Bay Of Bengal on May 27, 2017. Heavy rain from Mora and it's remnants moved over southeastern Bangladesh and northeastern India. Monsoon rainfall also started to move into southern India.
The monsoon is a seasonal rain and wind pattern that occurs over South Asia (among other places). Through NASA satellites and models we can see the monsoon patterns like never before.
Monsoon rains provide important reservoirs of water that sustain human activities like agriculture and supports the natural environment through replenishment of aquifers. However, too much rainfall routinely causes disasters in the region, including flooding of the major rivers and landslides in areas of steep topography.