Friday, November 11, 2022
The skies were dark, looming and ominous with pregnant rain clouds. I did not join Palayam for the beach walk this morning. But Palayam is not one to miss even a day’s observation. Since September 2018, he has been taking daily early morning observations of wind, current and sea conditions at Urur Kuppam. I transcribe his “data” onto a spreadsheet. Since October 2022, we have added two more observations for wind – at noon and 10 pm.
It was 6 am when Palayam sent me a detailed voice note expressing doubt over the Red Alert warning of heavy rains in Chennai on 10 November. Fishers rely on palpable signs from the sea, seashore and winds to read storms. All signs certainly indicated that stormy weather is in the offing. The intertidal seafloor was not firm, but squelchy beneath the feet. Thangamani’s net had brought in nearly Rs 5,000’s worth of otta kavalai (sardinella), a sure indicator that a kadaveri (sea storm with zero fishing prospects) was imminent.
But Palayam was skeptical about heavy rains. “We will have rains in spells, but I doubt that they will be anything like the rains of November 2021,” he told me. His voice note records as follows: “The clouds are fearsome and dark, and it looks like it’s going to pour and pour. But there is more wind than rain – the Kun Vaadai storm winds from the north-northwest. Last night, very chill moisture-laden winds blew in from the north and northeast. Our elders used to refer to such winds as ootha kaathu. “Look, the icy cold ootha kaathu is coming,” they’d say.”
“Icy cold” is a bit of a stretch, but understandable if one accounts for the fact that Palayam is from Chennai, where sweaters and chinese ear-muffs are brought out when temperatures plummet to the low 20s (degrees celsius).
Fisher science is starkly different from institutional science when it comes to reading weather systems. Currents are the kingmakers that can block, allow or intensify rain. The stronger the northerly Vanni current is both nearshore and at midsea, the more intense the rain event is likely, provided the other two necessary conditions are satisfied – i.e. northerly Vaadai winds, if not the Kun Vaadai (NNW) which signals a storm, and the presence of rain clouds. When a strong Vanni and Kun Vaadai meet on a cloudy day, you should beware: the heavens will pour.
When Palayam voiced his opinion on the unlikelihood of heavy rains, Kun Vaadai winds were gusting and the sky was dark with rain clouds. But the nearshore and midsea currents were weak. Nearshore currents are easy to gauge: Fling a piece of wood into the waves and see if it drifts south or north. Midsea currents can be sensed by watching how the ships near the harbour drag on their anchors. If their bow-stern points north-south, the current is a northerly Vanni.
But when Palayam entered his data in the early hours of 10 November, visibility over sea was poor. The ships were shrouded by a thick mist. Then, how did he sense the nature of the current out at sea? Palayam explains in his voice note: “The sea is very turbulent. The waves are froth-tipped and have a spring to them. A strong current would have automatically calmed the seas. The turbulence tells me there is no current. Looking at the waves washing in, I see that each wave that forms out at sea washes all the way up the shore, with hardly a gap between one wave and the next. When this happens, we say “Kadal virichalaa irukku. The sea is in a virichal state.””
It is impossible to take a boat out in such conditions – the sea is in a churn all the way from the kadaladi (foreshore) and naduthambu (end of surf zone) to the mela kadaladi (aft shore).”
Friday. 12 November, 2022.
The Indian Express reports that the city received 64.5 mm rain in the 24 hours ending 8:30 am today. As Palayam had predicted, the day was wet but the rains were neither intense (more rain in less time) nor heavy in absolute terms. Contrast that with the 200 mm of rain that fell in just five hours on November 8, 2021 – an hourly average of 40 mm.
Such intense rain events can overwhelm drains and inundate neighbourhoods.
This morning, Palayam sent another voice note at around 5.45 a.m. from his observation perch near Broken Bridge. A strong Eeran wind was blowing in from the east. “I suppose you witnessed the happenings early in the morning. That thunder was like I have never heard before. And the wind was strong too. Whenever thunder and winds combine like this, they will extinguish the rains after a few hours of downpour,” Palayam recorded in the voice note.
I called him in response to his voice note to get some clarifications. He said: “The wind is tending to blow as a Kachan Eeran (from southeast), as a thennal – a calming breeze that will ease the turbulence in the sea, and usher in good fishing in the days to come. That will happen if the low pressure moves north along Tamil Nadu’s coast. If on the other hand, the low pressure turns towards Arabian Sea without coming along our coast, we will continue to witness northerlies, and the sea will remain turbulent.”
The Met department has announced that the low pressure will move along our coast in a northwesterly direction, make landfall and continue over land to cross Kerala and emerge as a low pressure over the Arabian sea.
It is now 12 noon. A few hours back Palayam noted that the winds and the sea had calmed considerably, and that a thennal was imminent. I called up Palayam to find out if the winds had shifted. He refused to indulge me. “Take your cycle and go to the seashore and tell me what you see. Will you believe anything I tell you?” he chided me. I said I had to finish and send this essay. “All the more reason for you to witness what you are about to write,” he insisted.
I went to the beach. The winds were still blowing from the east, but tending to shift to the northeast. There was no sign of a thennal. By the time I returned home, Palayam was calling me from the beach. “What did you see?” he asked. I reported back. “Strange. Just two hours back, the winds made it seem as though they would blow from the southeast (thennal). But now, the sea is back to being rough and the wind is tending to a Vaadai Eeran (northeasterly). The Vanni current has stopped flowing out at midsea. The ships at anchor are pointed east indicating that the bottom current is dead, with only an easterly Olini current flowing.”
It is easy to tell when the Olini pushes landward. The sea will have bands of colour – muddy closer to shore and the blue of the deep further offshore.
I told him about the Met department’s observations. “There is still a chance that a thennal may set in by nightfall. Let’s wait and see.”
Sunday, November 13, 2022
Palayam’s voice note recorded at 5.07 a.m. from Broken Bridge reports that the thennal had set in, albeit only tentatively. The wind was gentle and from the southeast – the breeze that soothes the sea. “All boats can set off today if they so desire. It will rain intermittently because the current is Vanni. But the sea is okay. It is unfortunate for us that the storm did not make landfall in Chennai. Fishing will be okay, but not as remunerative.
Further south, where the storm crossed our coast, there will be happy fishing. Here, the Paruvu is likely to form further out at sea, not nearshore because the storm was not intense here. Where the storm crossed the coast, Paruvu is likely even closer to shore.”
By 7 am, though, the wind had shifted once again to blow again as a Kun Vaadai storm wind, with a burst of rain and thunder. The winds will keep shifting today, he said.
Note: Paruvu is a marine phenomenon that accompanies turbid sea conditions that results in the congregation and gregarious movement of several commercially valuable fish. The opposite of Paruvu is Marappu, which occurs when the seas are clear and emptied of commercially valuable fish.