North Atlantic Ocean: Hurricane Larry tracking north-northeastward in North Atlantic Ocean early Sept. 11 /update 7

Event

Hurricane Larry is tracking north-northeastward in the North Atlantic Ocean early Sept. 11 following landfall west of Long Harbour on western Avalon, Newfoundland and Labrador Province, Canada at around 00:01 AST Sept. 11. As of 05:00 AST, the system's center of circulation was approximately 455 km (285 miles) north-northeast of Cape Race, Newfoundland.

Forecast models indicate that the system is likely to weaken as it continues northeastward and enters the Labrador Sea, transitioning into a post-tropical cyclone with tropical-storm-strength winds by the afternoon of Sept. 11. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

Reports indicated that more than 50,000 people are without power as of early Sept 11, with the most affected from the Avalon Peninsula. The Town of Marystown on the Burin Peninsula is under a boil water advisory due to a power failure at the water treatment plant. Officials may update information on damage and disruptions caused by Larry as clean-up and repair efforts continue.

Government Advisories
As of 05:00 Sept. 11, the Meteorological Service of Canada has issued hurricane, tropical storm, wind, storm surge, and/or heavy rainfall alerts in the following locations:

• Newfoundland and Labrador Province: Avalon Peninsula North, Avalon Peninsula Southeast, Avalon Peninsula Southwest, Bonavista North, Bonavista Peninsula, Burin Peninsula, Cartwright to Black Tickle, Clarenville and vicinity, Connaigre, Eagle River, Northern Peninsula East, Port Saunders and the Straits, Postville - Makkovik, Rigolet and vicinity, Saint John's and vicinity, Terra Nova, and Upper Lake Melville

For a detailed list of such alerts, click here.

Hazardous Conditions
Significant swells will continue to affect Atlantic Canada, causing life-threatening surf and rip current conditions through Sept. 11. Water levels due to storm surge are forecasted to gradually subside through Sept. 11.

Sustained heavy rainfall could trigger flooding in low-lying communities in Newfoundland over the coming days. In addition to the heavy rain, flooding, and storm surge, the storm could produce damaging wind gusts, resulting in power outages due to uprooted trees and toppled utility lines. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall.

Prolonged sea swells and storm surge generated by the system will likely result in coastal flooding as the system approaches land. Persistent onshore flow could make it difficult for surge to recede and for water levels to decrease in coastal river catchments. In addition to the heavy rain, flooding, and storm surge, Larry could produce damaging wind gusts, resulting in power outages due to uprooted trees and toppled utility lines.

Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports. As of early Sept. 11, authorities have canceled some flights at St. John’s International Airport (YYT). Flights are likely to resume by Sept 11 as the weather improves.

Disruptions triggered by inclement weather and resultant hazards, such as flooding could persist well after conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.

Health
The latent threat of waterborne contaminants from inundated industrial sites cannot be discounted; exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.

Advice

Activate contingency plans in areas forecast to be impacted by the storm. Use caution in low-lying areas due to the high potential for flooding. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers.

Resources

US National Hurricane Center
National Weather Service
Meteorological Service of Canada