Lok Sabha Question No. 700 (UNSTARRED), answered on 2024-02-07
Subject: Rainfall Forecasting
Ministry: EARTH SCIENCES
Asked by: P. Velusamy, S.R. Parthiban

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES LOK SABHA

## UNSTARRED QUESTION NO. 700 TO BE ANSWERED ON WEDNESDAY, 7 TH  FEBRUARY, 2024

## RAINFALL FORECASTING

## 700.    SHRI VELUSAMY P.: SHRI PARTHIBAN S.R.:

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) whether  the  Government  proposes  to  take  efficacious  measures  to  monitor  the  nonforecasted heavy rains and waterlogging and if so, the details thereof;
- (b) whether the Government proposes to strengthen the monitoring mechanisms to detect and forecast cloud bursts;
- (c) if  so,  whether  the  Government  is  likely  to  revisit  the  flood  management  policies  to strengthen the skillful and precise forecasting mechanisms of rainfall in the wake of the frequent cloud bursts causing flash floods;
- (d) whether  the  Government  proposes  to  take  appropriate  and  time-bound  measures  for mapping the cloud burst-prone regions across the country; and
- (e) if so, the details in this regard?

## ANSWER

## THE MINISTER OF EARTH SCIENCES (SHRI KIREN RIJIJU)

- (a) India  Meteorological  Department  (IMD)  is  continuously  enhancing  and  upgrading  the meteorological  observations,  communications,  modeling  and  forecasting  system.  The forecasts and warnings are issued at  the national,  State and  district  levels.  Most  of the forecasts are remain within the forecast limit or close to the error limit. There has been about 40% improvement in forecast accuracy of severe weather events including heavy rainfall events in recent five years compared to previous years.
- (b) As cloud bursts are highly localized and are of very short duration and hence challenging to forecast.  However,  Ministry  has  taken-up  various initiatives to strengthen  the monitoring  mechanisms  for  the  timely  detection  and  accurate  forecast  of  cloud  bursts. Currently, IMD utilizes Radio Detection and Ranging (RADAR) system, Automatic Rain Gauges (ARGs) for monitoring these events. These datasets will be assimilated into the IMD's  High-Resolution  Rapid  Refresh  Modeling  System  (IMD-HRRR)  and  Electric Weather  Research  and  Forecasting  (EWRF)  models  to  better  capture  and  forecast  the cloud bursts.
- (c) IMD supports floodwarning services of Central Water Commission (CWC), Ministry of Water  Resources  by  providing  observed  and  forecasted  rainfall.  Heavy  rainfall  events lead  to  floods  over  different  river  basins  of  the  country.  In  order  to  meet  specific requirements of flood forecasting by CWC, IMD operates Flood Meteorological Offices (FMOs) and provides Quantitative Precipitation Forecast (QPF) for all river catchments.

In order to cater the services of hydro-meteorological events occurring in short duration of  time,  IMD  is  issuing  Flash  Flood  Guidance  (FFG)  by  which  the  volume  of  water within  a  watershed  required  to  produce  flooding  at  the  outlet  of  the  catchment  is estimated. The FFG bulletin is generated on daily basis since 2020 and disseminated to the users including CWC every six hours on routine basis. The FFG is a robust system designed to provide  the necessary products  in real-time  to support the development  of warnings  for  flash  floods  about  6-24  hours  in  advance  at  the  watershed  level  with resolution of 4 km x 4 km for the flash flood prone regions.

- (d)-(e)  Cloud  bursts are  highly  localized and are  of very short duration and most of the cloud bursts occur over hilly region. Some studies which have been conducted with limited data indicate that southern rim of the Indian Himalayas especially over Uttarakhand, Himachal Pradesh and hilly areas of northeast India are prone to cloud bursts.West coast of India covering  windward side of  Western  Ghats  from  Goa  to  Gujarat  is  also  prone  to  cloud bursts. Further, the regions with height of elevation of 1000 m to 2500 m have been more vulnerable to cloud bursts.

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