RIMES Terms Titli Cyclone ‘Rarest of Rare’ | 26 Nov 2018

• The Regional Integrated Multi-Hazard Early Warning System (RIMES) for Africa and Asia, has termed ‘Titli’, the severe cyclonic storm that hit Odisha as ‘rarest cyclone’.
• Titli cyclone was the rarest of rare in terms of its following characteristics:
  • Recurvature after landfall.
    • When the eye of the storm passes over land, it is classified as making landfall.
    • The eye of a hurricane has comparatively light winds and mild weather, while the eyewall is a ring of thunderstorms surrounding the eye.
    • The eyewall can actually hit land without the cyclone "making landfall". E.g.: Hurricane Sandy made landfall in Cuba and Jamaica, but it was Haiti that was hit hardest.
  • Retaining its destructive potential after landfall,
  • Recurvature away from the coastal areas for more than two days,
  • No synthetic track projection available to capture the Titli type of cyclones,
  • Damage to both life and property caused in interior districts.
• Earlier, India Meteorological Department had also called the formation of Titli as a ‘rarest of rare’ occurrence.
• Usually, cyclone-risk management are heavily focused on the coastal areas where cyclones cross at their peak intensities. Therefore, coastal areas now have been largely well managed through evacuations and other protocols, leading to zero casualties. However, this is not true for the interior regions since a Cyclone’s intensity weakens as it moves away from coastal areas.
• The RIMES has recommended that a detailed risk assessment be carried out for Odisha to understand the risks in the light of the Titli devastation.

Movement of Cyclone

• The cyclones that typically strike the Indian neighbourhood in the northern hemisphere rotate anticlockwise.
• Their normal behaviour is to derive strength from the moisture in waters such as the Bay of Bengal, move west, incline in a northerly direction and peter out into the sea or land, depending on their origin.
• In a re-curving cyclone, the cyclone gets a sort of second wind when it is on the wane.
• It is deflected right or eastwards. This is due to air currents in the local atmosphere that push cold air from the poles towards the equator and interfere with cyclone formation. That is what make them ‘re-curving.’
• In the southern hemisphere, the cyclones spin clockwise and therefore also re-curve in the opposite direction.
• A challenge with re-curving cyclones is that it is hard for weather models to pick them early on — as was the case with Ockhi — and so they pose unique challenges in terms of hazard preparedness and disaster management.

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