Saturday, June 19, 2021

international

India braces for second hurricane-strength storm in 10 days


For the second time in 10 days, India is set to be slammed by a powerful cyclone, or a hurricane-equivalent storm, bringing the risk of damaging winds, storm surge and heavy inland rainfall. The system, known as Yaas, is currently only a tropical storm as it swirls over the Bay of Bengal. But it is expected to intensify into a high-end Category 1-strength tempest before its midweek landfall along Indias northeast coast.

The anticipated landfall comes just nine days after Gujarat, India, was slammed by Extremely Severe Cyclonic Storm Tauktae, which made landfall last Monday Eastern time as a high-end Category 3-equivalent storm with 125 mph winds. Its landfall coincided with a report of the nation's deadliest day of the covid-19 pandemic, a staggering 4,329 deaths recorded.

At least 86 people were killed by the storm, which caused an estimated $2.1 billion in damage, according to RMSI, a global catastrophe risk management consultancy.

Now a new system is brewing, not in the Arabian Sea but rather to the east of India. Tropical Storm Yaas had winds of 40 mph early Monday Eastern time, making it a borderline tropical storm. But it is set to intensify steadily over the coming days, and it should wrap into a solid hurricane-strength cyclone by late Tuesday as landfall nears. It was located about 400 miles away from its imminent landfall location early Monday, moving north-northwest at about 4 mph.

The India Meteorological Department has hoisted rainfall and wind warnings for the states of Odisha and West Bengal. Local authorities have been working to ensure the safety of oxygen generation plants amid the ongoing covid-19 crisis.

On satellite, the storm had a robust shield of cloud cover spiraling into it from the west, but bare ocean could be seen through gaps in low-level clouds east of the center. That's usually a sign of dry air, but in this case, the environment surrounding Yaas is saturated, save for a narrow strip of dry air east of the storm at 30,000 feet. As such, it looks like Yaas's lopsided appearance isn't so much an indicator of obstacles impeding Yaas's development as it is a symptom of the storm's gradual maturation.

While sea surface temperatures are warm and sufficiently toasty to support a strong cyclone, a change of wind speed and/or direction with height, known as wind shear, is working to disrupt Yaas's circulation. That effect is being somewhat counteracted by effective northerly outflow, or the evacuation of air exiting the storm at high altitudes, which allows the system to ingest more air and strengthen.

Together, the effects roughly balance out, meaning Yaas will probably strengthen right up to the point of landfall. The Joint Typhoon Warning Center is calling for Yaas to be a 90 mph Category 1-equivalent storm with gusts to 115 mph as it moves ashore overnight Tuesday into early Wednesday.

Right now, it's looking like the states of Odisha and West Bengal are at greatest risk for a direct strike from Yaas; computer models are in good agreement regarding the anticipated track of the storm. Winds gusting over 80 mph are likely where the storm makes landfall, with perhaps a 3- to 6-foot storm surge east of the center.

Atop the increase in sea level, large waves could exacerbate flooding concerns in coastal areas.

"Tidal waves of height 2 to 4 meters above astronomical tide are likely to inundate low lying coastal areas of . . . Parganas, Medinipur, Balasore, Bhadrak, Kendrapara and Jagatsinghpur Districts around the time of landfall," the India Meteorological Department wrote.

If the storm comes ashore where currently simulated, it could pose a surge problem for cities such as Haldia and Kolkata. They are situated on the Hooghly River, which opens to a bay at the coastline. An onshore southerly flow could push water into the bay and inundate some coastal areas.

The surge is unlikely to reach Kolkata, but high water downstream may back up the Hooghly River, which will simultaneously be working to drain heavy rainfall. A broad 3 to 6 inches of rain is likely east of the center, with 6 to 12 inches possible west of the circulation.

The two cities are among many in the region largely dependent on fishing and marine commerce. Offshore waves could top 60 feet during the height of the storm, prompting a stern warning to mariners.

"The fishermen are advised not to venture into central Bay of Bengal during 24th - 25th May and into north Bay of Bengal and along and off north Andhra Pradesh-Odisha-West Bengal-Bangladesh coasts from 24th - 26th May," cautioned the India Meteorological Department.

 

The storm should dissipate by late Wednesday or early Thursday as it drifts inland to the northwest, bringing some rain showers to the high terrain of northern India to close out the workweek.

Published : May 25, 2021

By : The Washington Post · Matthew Cappucci