Cyclone Vardah: Here's what landfall is...

Heavy rains accompanied by high velocity winds on Monday pounded Chennai and coastal districts of north Tamil Nadu.

Pic courtesy: @ndmaindia

Chennai: Heavy rains accompanied by high-velocity winds on Monday pounded the city and coastal districts of north Tamil Nadu due to severe cyclonic storm "Vardah" which began making landfall near here, uprooting hundreds of trees, disrupting land and air transport and throwing normal life out of gear.

Following is what is 'landfall':

- Landfall is the event of a storm moving over land after being over water. 

- The National Hurricane Center defines landfall as - "The intersection of the surface centre of a tropical cyclone with a coastline. Because the strongest winds in a tropical cyclone are not located precisely at the centre, it is possible for a cyclone's strongest winds to be experienced over land even if landfall does not occur. Similarly, it is possible for a tropical cyclone to make landfall and have its strongest winds remain over the water. Compare direct hit, indirect hit, and strike."

- Generally, a landfall is accompanied by strong winds, severe rain and high sea waves.

- Landfall is different from where the core of high winds (or eyewall) comes onshore but the center of the storm may stay offshore. However, the effects of these are said to be similar to a landfall.

- A tropical cyclone is classified as making landfall when the centre of the storm moves across the coast. When a tornadic waterspout makes landfall it is reclassified as a tornado. When a fair weather waterspout makes landfall it usually dissipates quickly.