Cyclone Yaas leaves a trail of destruction but strengthens monsoon winds
Very severe Cyclone, Yaas, made landfall about 25 to 30 km south of Balasore in Odisha on Wednesday morning, packing winds of 130 to 140 kmph gusting to 155 kmph, according to the India Meteorological Department (IMD).
It weakened marginally immediately after landfall but continued to be a very severe cyclone for a couple of hours more and a severe cyclone with wind speed of 100 to 110 kmph gusting to 120 kmph over land by the evening.
“Yaas did not intensify further because it was relatively closer to the coast, the vertical wind shear (change in wind direction and speed at different heights) was not favourable and the sea surface temperatures were slightly lower near the coast. It may have intensified further, if not for these factors,” said Sunitha Devi, in charge, cyclones at IMD.
Yaas is likely to move north-northwestwards and weaken gradually into a cyclonic storm during the next 6 hours, IMD said in its 2.30pm bulletin. It did not intensify rapidly and that could have multiplied the damage over Odisha and West Bengal coasts several fold.
“Unlike Tauktae, after landfall, westerly dry winds affected Yaas which helped it dissipate. The moisture feed was reduced. Now it will remain a cyclone or a deep depression till Thursday morning,” said Mahesh Palawat, vice president, Skymet Weather.
Parts of Odisha reported extremely heavy rain on Wednesday — Chandbali 29cm; Garadpur and Rajkanika 25cm each; Balikuda 19cm; Tirtol and Binjharpur 21cm each; and Paradip 20cm. Over Tamil Nadu, Kanyakumari recorded 24cm; over Kerala, Idukki recorded 19cm; and Thiruvananthapuram 17cm. IMD scientists said Yaas had helped strengthen monsoon winds and that monsoon onset over Kerala is likely next week.
High waves in the range of 3.5 to 9.8 metres are forecasted for parts of both Odisha and West Bengal coasts from Wednesday evening to Thursday evening by Indian National Centre for Ocean Information Services (INCOIS). Extremely high waves were also recorded before and immediately after the landfall of Yaas but the height is yet to be validated through measurements on ground, IMD officials said.
Independent experts said that both Arabian Sea and Bay of Bengal were exceptionally warm, making them favourable for development of powerful cyclones this month.
“The similarity between Cyclone Yaas and Tauktae is that both are preceded by very high sea surface temperatures reaching 31– 32°C. These high temperatures were conducive for cyclone Tauktae to intensify into an extremely severe cyclone in a short time. Similarly, high temperatures are predicted to assist Yaas also for intensifying rapidly. However, there is one difference. Tauktae spent several days in the Arabian Sea where it could draw the heat and moisture continuously, reaching peak intensity of more than 220 km/hr. In the case of Yaas, it has formed in the north Bay of Bengal, and the travel distance to landfall is shorter. Here the common thread is that rising ocean temperatures in both the basins assisted these cyclones in their rapid intensification process,” said Roxy Mathew Koll, a climate scientist at Indian Institute of Tropical Meteorology in a statement.
According to IMD, Yaas may weaken to a depression only on Thursday morning. “Severe cyclone Yaas is moving towards Jharkhand. It will dissipate gradually reaching the intensity of a depression on Thursday morning. Till then its likely to bring a lot rain in its path,” added Sunitha Devi.
Light to moderate rain at most places with heavy to very heavy rains and extremely heavy rain (over 20cm) is likely at few places over north interior Odisha during the next 24 hours and heavy to very heavy rainfall at isolated places over coastal Odisha during the next 12 hours. Moderate to heavy rain is likely over Medinipur, Jhargram, Bankura, South 24 parganas, Purulia, Nadia, Murshidabad, East Bardhaman, Howrah, Hooghly, Kolkata, North 24 Parganas, Haldia, Darjeeling, Kalimpong districts in West Bengal on Wednesday. Over Jharkhand very heavy to extremely heavy rain is likely at isolated places on Wednesday and Thursday.
Experts said monsoon may arrive over Kerala a day in advance, as predicted by IMD. “Yaas helped pull the monsoon current head in the Arabian Sea. There was heavy to very heavy rain reported in many parts of Kerala in the last 24 hours so we are expecting monsoon to arrive early,” said Palawat.
“Monsoon is likely to be on time. But we still have a few days, so we can’t say anything immediately. Let’s watch how conditions become favourable for its onset,” said M Mohapatra, director general, IMD.
“Cross equatorial flow over the Arabian Sea has strengthened because of which very heavy rain was reported over Kerala. But that is not monsoon rain. We are expecting monsoon to arrive on May 31 or June 1,” said OP Sreejith, scientist and head, Climate Monitoring and Prediction Group.
Monsoon is likely to arrive over Kerala on May 31, a day ahead of its normal arrival date of June 1, with a possible error margin of plus/minus four days, IMD had said on May 14.