10 Oct 2021 | 11:10 PM UTC
Pacific Ocean: Tropical Storm Pamela forms in Pacific Ocean Oct. 10
Tropical Storm Pamela forms in Pacific Ocean Oct. 10; landfall as Category 2 hurricane forecast over Mexico's Sinaloa State late Oct. 13.
Event
Tropical Storm Pamela formed in the Pacific Ocean Oct. 10. As of 16:00 CDT, the storm's center of circulation was approximately 425 km (265 miles) south-southwest of Manzanillo, Mexico.
Forecast models indicate the system will continue tracking west-northwestward Oct. 10 before turning northward late Oct. 11. TS Pamela will then track northeastward passing south of the Baja California peninsula late Oct. 12.
The system is forecast to strengthen over the coming days and make landfall as a Category 2 storm over Mexico's Sinaloa State late Oct. 13. Pamela will then rapidly weaken as it tracks overland across parts of Mexico's Durango, Chihuahua, and Coahuila states before dissipating by early afternoon Oct. 15. The storm's track and intensity forecast remain somewhat uncertain, and the system may change accordingly over the coming days.
Government Advisories
Authorities will likely issue warnings or advisories in response to the system's progression in the coming days. Tropical Storm Pamela will likely bring heavy rainfall, strong winds, and rough seas to coastal areas of west-central Mexico, especially Baja California Sur and Sinaloa states.
While widespread rain accumulations are possible across affected areas through at least Oct. 14, locally higher rainfall totals could occur in locations affected by persistent bands of thunderstorms as the storm approaches/passes. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall.
Fairly arid areas may also be subject to inundation where hard, dry soil cannot absorb rainfall. Rain-induced landslides are possible in steeply sloped terrains; surface runoff in desert locations and along old bushfire burn scars could also result in dangerous mudslides. Flooding could isolate some communities for several days. Prolonged swells and storm surge generated by the system will likely result in coastal flooding as the storm approaches land. Abnormally high tides are likely through at least Oct. 14, which will exacerbate storm surge throughout west-central Mexico.
Persistent onshore flow could make it difficult for the surge to recede and for water levels to decrease in coastal river catchments. Tropical Storm Pamela will produce damaging wind gusts as it approaches affected areas in west-central Mexico. Gusts in excess of 175 kph (110 mph) cannot be ruled out, especially in areas near the center of circulation. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible.
Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions. Floodwaters and debris flows could render some bridges 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.
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
Stagnant pools of water during and after flooding increase the incidence of insect- and waterborne diseases, such as dengue fever, cholera, and malaria. The threat of these disease outbreaks is usually elevated in low-income or underdeveloped areas of major urban centers due to the presence of incomplete or open sewer lines. 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 where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge.
Stockpile water, batteries, and other essentials in advance. 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. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.
Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.
