Hailstorm climatology over Maharashtra with associated impacts and risk assessment

Against the backdrop of climate change and the expected increase in extreme weather events, the present study aims to provide an integrated assessment of hailstorm climatology, its associated impacts and risk across Maharashtra, where such events are episodic and often devastating. This is undertaken through detailed analysis of past characteristics of the hailstorms and associated impact on a district level for a period of 30 years (1991–2020) by the synthesis of information from official weather reports of India Meteorological Department, media reports, as well as state government reports of the impact of hailstorms. The results indicate that, of the total hailstorm days analyzed, 42% were moderate hailstorm days and 58% were heavy hailstorm days with the frequency of moderate events increasing in recent years. February emerged as the month with maximum hailstorm activity followed by March and April. The hailstorm activity peaked between 04:30 and 05:30 PM IST accounting for approximately 40% of the total events. A secondary peak, with around 20% of the total occurrences was observed between 05:30 and 06:30 pm IST. The median duration of hailstorms was found to be 10 min. The spatial distribution of hailstorm events across seasons indicated that, although hailstorm activity was reported across Maharashtra in all the seasons, highest hailstorm activity was recorded during March, April and May, particularly over interior Maharashtra. District wise in Maharashtra, Nagpur recorded the highest hailstorm activity across all seasons with heavy hailstorm activity predominantly observed from March to May and October to December. On an annual scale, hailstorm occurrences exhibited an increasing trend across most districts of Maharashtra. A significant rising trend (at the 95% confidence level) was observed over a contiguous area covering Marathwada (Jalna, Parbhani, Hingoli and Nanded) and South Madhya Maharashtra (Satara and Sangli). This study also indicates that the agricultural sector experienced the most significant damage with moderate and heavy hailstorms contributing almost equally. Additionally, higher population density increases the likelihood of casualties and injuries. Consequently, considering agricultural area and population density as exposure indicators and following the IPCC 2014 framework, Normalized Vulnerability Index (NVI) was calculated district-wise using appropriate indicators for adaptive capacity and sensitivity. Risk was then determined as the product of vulnerability, hazard and exposure, with hailstorm as hazard element. District-wise analysis clearly demonstrates that Vidarbha and parts of Madhya Maharashtra exhibit moderate to high vulnerability due to large agricultural footprints, relatively higher poverty, and infrastructural constraints. Nashik and Nagpur emerged as the most vulnerable with Nagpur being the only district in Maharashtra classified under Very High-Risk category. This information will be valuable not only for issuing day-to-day impact-based weather forecasts for hailstorm but also to disaster managers for planning effective mitigation measures of this weather hazard in Maharashtra.