T.N. Niyas’s research while affiliated with India Meteorological Department and other places

Kerala, located at the southwest tip of India, witnessed disastrous floods during the monsoon seasons of two consecutive years, 2018 and 2019. This paper provides a detailed analysis of these two flood events using data from multiple sources. The unusually unstable and convective nature of the 2019 event, as detectable in its higher cloud tops and evidently fuelled by anomalously warm local sea temperatures, raises concerns regarding the changing patterns of rainfall over the southern parts of the west coast of India. Specifically, our analysis reveals that the flood of 2019 in Kerala satisfies the criteria for a mesoscale cloudburst (MsCB) event, more common in the north but a very rare and never before reported phenomenon in the Kerala region. Rainfall exceeding 50 mm in 2 h has been reported from many places between 8.00 and 22.00 UTC on the August 8, 2019. Satellite-derived rainfall and cloud microphysical parameters further reveal the uniqueness of the 2019 MsCB event. If 2019 is a harbinger of how global warming may continue to affect this region, transformations of the cloud structure and the recurrence and character of intense rainfall events could pose a major threat to the highly vulnerable Western Ghats ecosystems.