Early Warning System and Phailin

By: L S Rathore and M Mohapatra
Cyclone Phailin crossed into Odisha and adjoining northern Andhra Pradesh near Gopalpur on October 12, 2013. India Meteorological Department (IMD) accurately predicted the genesis, intensity, track and point and time of landfall well in advance. As a result, the loss of human lives due to the cyclone was reduced to just 22 persons.
Disaster Events

Cyclone Phailin crossed into Odisha and adjoining northern Andhra Pradesh near Gopalpur around 1700 UTC on October 12, 2013 with a maximum sustained wind speed of 215 kmph. Consequently 22 human lives were lost. This was in sharp contrast to 10,000 lives being lost in the October 29, 1999 Odisha Super Cyclone. Hence, a study was undertaken to analyse the early warning system used for tackling Phailin with the intention of improving disaster management during impending future natural disasters. India Meteorological Department (IMD) accurately predicted the genesis, intensity, track and point and time of landfall 4-5 days in advance. An analysis of what limited the loss of lives proves that effective co-ordination between various stakeholders can work wonders.

 

Phailin Vs Odisha Super Cyclone

Phailin, meaning sapphire in Thai, followed a course similar to the Odisha Super Cyclone (1999) which made landfall with 140 knots maximum sustained winds. However, the death toll and destruction to property due to Phailin was considerably minimised due to a proactive three-tier disaster management through agencies at the central, state, and district levels. Accurate forecasts and warning services by the IMD based on the Numerical Weather Prediction (NWP) model should be credited for the successful prediction. In contrast, there was only a one day advance warning using inaccurate bulletins during the 1999 Odisha super cyclone.

Consistent prediction of the place, time and the associated adverse weather at landfall by the forecasters and mitigation strategies by disaster management experts in anticipation of cyclone Phailin helped evacuate more than one million people to coastal shelters across 18,000 villages in Odisha and Andhra Pradesh. Increased awareness also helped public realise the severity of the threat and had them pay attention to warnings issued.

 

Operational TC forecasts of IMD

The success of Phailin is not an event in isolation. It is the culmination of a sustained investment in research and development of numerical models, observations, and data assimilation techniques and above all, multiple media sources for forecast dissemination across the region. Until 2003, coarse resolution Quasi Lagrangian Model (QLM) that could provide track guidance for only 24 hours were in use at the IMD. Thanks to a modernisation programme, several in-house models were introduced for prediction, such as the IMD Global Forecast System (GFS), the National Centre for Medium Range Weather Forecast (NCMRWF), India GFS, the National Centre for Atmospheric Research (NCAR) version of Weather Research and Forecasting (WRF), and the National Oceanic Atmospheric Organisation’s (NOAA) Hurricane WRF (HWRF) system. In addition, several products from international models are now readily available to forecasters. A single model ensemble prediction system (EPS) from various global models and multi-model ensembles (MME) were also introduced. Based on this, the official forecast was extended up to 72 hours in 2009 and up to 120 hours in 2013.

In the case of Phailin, IMD began forecasting from October 7, 2013, when it formed over the Andaman Sea as a low-pressure area. In spite of the large spread of the system, the IMD predicted a precise landfall between Kalingapatnam (north Andhra Pradesh) and Paradip, close to Gopalpur (south Odisha) with an advance 96 hour forecast.

 

Advances in adverse weather forecast in recent years

Beyond the wind and rain-induced flooding, a storm surge creates havoc in low-lying densely populated coastal areas in eastern India, which has a large network of rivers. About 80 per cent of the mortality during the 1999 Odisha super cyclone and Nargis (2008) was due to storm surges. Therefore, storm surge estimation is vital for disaster mitigation and management.

Since 2009, IMD has been using dynamical surge models developed at the Indian Institute of Technology (IIT) Delhi. Prior to this, a statistical-empirical method, nomogram, was in practice. The operational storm surge model forecast was limited to 24 hour forecast guidance mainly due to lack of more realistic inputs of TC track, intensity and size. IMD utilised the storm surge models of IIT Bhubaneswar, IIT Delhi, and the Indian National Centre for Ocean Information Services (INCOIS), Hyderabad for storm surge forecasts during Phailin. Further, output from the coastal inundation model of INCOIS was utilised experimentally to provide information on the expected location-specific extent and depth of inundation. Thus, an ensemble of operational and experimental model products were used by forecasters for improved storm surge and coastal inundation forecast guidance during Phailin aiding the evacuation of people from hazard-prone regions.

 

Advances in forecast dissemination

Prior to 2009, TC warnings by the IMD were not as exhaustive and dissemination was limited to radio, television, newspapers, telephone and fax. In recent years, and particularly during Phailin, the IMD adopted advanced strategies such as warning bulletins (within three hours of observation) and hourly updates through dedicated web, sms, e-mail, telephone, telefax, television, radio, and other social networks to the public as well as the respective state governments, port officials, the National Disaster Management Authority (NDMA), and the control room of the National Disaster Management Cell of the Ministry of Home Affairs. In addition, a wide range of telecommunication channels such as VHF/HFRT, satellite-based cyclone warning dissemination system (CWDS), aeronautical fixed telecommunication network (AFTN, aviation), interactive voice response system (IVRS) were also used for warning dissemination. Daily press releases and conferences with press and electronic media were organised. On a few occasions, IMD forecasters and the chief disaster managers at the national and state level conducted joint press conferences. The consistency in the forecast and warnings issued by the IMD together with regular coordination with disaster managers helped maximise the effectiveness of the warnings.

 

Endnote

Improved forecast guidance based on the NWP model for movement, intensity, structure, and storm surge of cyclone Phailin and enhanced warning products and dissemination systems collectively helped limit the death toll. Lessons learnt during the Phailin will need to be the building blocks for further improvement of early warning systems and disaster management in India.

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