Alert Details

  • Incident: Hurricane Delta
  • Location(s): Southern and eastern US (map)
  • Projected Landfall (Date): Southwestern Louisiana, US (late Oct. 9)
  • Center of Circulation: Approximately 551 km (343 miles) south-southwest of Cameron, La., US
  • Maximum Sustained Winds: 110 knots (205 kph, 125 mph)

Summary

Warning Alert

Hurricane Delta strengthens as it tracks in Gulf of Mexico, Oct. 8. Landfall likely in southwestern Louisiana, US, late Oct. 9.

Hurricane Delta has re-strengthened into a category-3 major hurricane as it tracks northward in the Gulf of Mexico, Oct. 8, following landfall on the Yucatan Peninsula near Playa del Carmen, Quintana Roo State, Mexico, the previous day. As of 1600 CDT, the system's center of circulation was approximately 551 km (343 miles) south-southwest of Cameron, La., US. Forecast models indicate Delta will continue to track northward in the warm waters of the Gulf of Mexico, which may allow the storm to strengthen further over the coming hours. However, the system is forecast to weaken slightly to a category-2 hurricane as it approaches landfall in southwestern Louisiana late Oct. 9. Impacts will likely be felt in portions of the Gulf Coast, US, beginning Oct. 9. Following landfall, the system will rapidly weaken as it tracks across the Gulf Coast region. Delta's remnants will likely bring heavy rainfall to portions of the eastern US, including the Mississippi Valley and Tennessee Valley regions, through at least Oct. 11. Some uncertainty remains in the track and intensity forecast, and changes could occur over the coming days, especially regarding potential impacts and landfall along the Gulf Coast of the US.

Government Advisories
As of 1700 CDT Oct. 8, the following warnings are in effect:

  • Hurricane Warning: High Island, Texas, to Morgan City, Louisiana
  • Tropical Storm Warning: West of High Island to Sargent, Texas; east of Morgan City, Louisiana, to the mouth of the Pearl River, including New Orleans; Lake Pontchartrain and Lake Maurepas
  • Tropical Storm Watch: East of the mouth of the Pearl River to Bay Saint Louis, Mississippi
  • Storm Surge Warning: High Island, Texas, to Ocean Springs, Mississippi, including Calcasieu Lake, Vermilion Bay, Lake Pontchartrain, Lake Maurepas, and Lake Borgne

Authorities could issue new warnings or update/rescind existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards. The possibility of localized evacuations cannot be discounted if weather conditions prove particularly hazardous. The proximity of the system's center of circulation to land will ultimately determine how significant the weather-related impacts will be; the greatest impacts will likely be felt just northeast of where the center passes.

 

Evacuations
In advance of Delta, a state of emergency is in effect for both Alabama and Louisiana. The following mandatory and voluntary evacuation orders have been issued:

  • Mandatory Evacuations (Louisiana): Calcasieu Parish; Cameron Parish; residents who live west of US Highway 90 and south of State Highway 14 in Iberia Parish; Jefferson Davis Parish; Grand Isle in Jefferson Parish; low-lying areas of Vermilion Parish; all areas south of the Morganza to the Gulf of Mexico levee system in Terrebone Parish; and south of the Intracoastal Waterway and west of the Wax Lake outlet in Saint Mary Parish
  • Voluntary Evacuations (Louisiana): Acadia Parish; Beauregard Parish; portions of Jefferson Parish, including Jean Lafitte, Lower Lafitte, Crown Point, and Barataria; Lafayette Parish; City of New Orleans, including Venetian Isles, Lake Catherine, and Irish Bayou; Lafourche Parish; Plaquemines Parish from White Ditch to Pointe a la Hache and from Phillips 66 Alliance Refinery to Venice; Port Fourchon; Saint Landry Parish; Saint Martin Parish near Stephensville and Belle River; and portions of Vermilion Parish south of State Highway 14
  • Mandatory Evacuations (Alabama): Orange Beach, Gulf Shores, Dauphin Island, Ono Island, and Fort Morgan

Hazardous Conditions
Hurricane Delta will likely bring heavy rainfall, gusty winds, and high waves to portions of the Gulf Coast beginning Oct. 9. Widespread rain accumulations around 13-25 cm (5-10 inches) are forecast across the southwestern and into south-central Louisiana. Locally higher rainfall totals up to 38 cm (15 inches) are possible in areas affected by persistent bands of thunderstorms. Rainfall totals of 8-15 cm (3-6 inches) are expected in far eastern Texas into northern Louisiana, southern Arkansas, and western Mississippi, with higher totals of up to 25 cm (10 inches) possible where the most persistent heavy rain bands occur. Additionally, rainfall accumulations of 2.5-7.5 cm (1-3 inches) are possible across the Ohio Valley and Tennessee valley over the coming days.

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. 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 system approaches the islands. A persistent onshore flow could make it difficult for the surge to recede, and water levels decrease in coastal river catchments.

The greatest impacts in terms of strong winds and storm surge will be felt just to the east of the center of circulation relative to the storm's track. This is partly due to the counterclockwise circulation of a hurricane in the northern hemisphere, which allows for a higher storm surge because the winds help bring additional water on to the shore. Forecast models indicate life-threatening storm surge totals of 2.1-3.4 meters (7-11 feet) are expected from Rockefeller Wildlife Refuge, Louisiana to Morgan City, Louisiana, including Vermilion Bay; surge of 1.2-2.4 meters (4-8 feet) is expected from Holly Beach, Louisiana, to Rockefeller Wildlife Refuge, Louisiana, Sabine Pass to Holly Beach, Louisiana, and Morgan City to Port Fourchon, Louisiana. Surge of 0.9-1.5 meters (3-5 feet) is forecast from Port Fourchon, Louisiana, to the Mouth of the Mississippi River and Calcasieu Lake. Storm surge levels of 0.6-1.2 meters (2-4 feet) are possible from High Island, Texas to Sabine Pass, the Mouth of the Mississippi River to Ocean Springs, Mississippi, Lake Borgne, Lake Pontchartrain, and Lake Maurepas. Surge levels of 0.3-0.9 meters (1-3 feet) are forecast from Ocean Springs, Mississippi, to the Alabama/Florida border including Mobile Bay, Sabine Lake, and Port O'Connor, Texas, to High Island, Texas, including Galveston Bay.

In addition to the heavy rain, flooding, and storm surge, the system is likely to produce damaging wind gusts as its center approaches the Gulf Coast. Hurricane-force gusts over 90 knots (165 kph, 100 mph) are possible along the Gulf Coast of the US near where the center of Delta makes landfall, including south-central and southwestern Louisiana; tropical-storm-force gusts in excess of 45 knots (85 kph, 50 mph) cannot be ruled out farther inland, as well as in far southeastern Texas and southeastern Louisiana. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible. Rain-induced landslides are also possible in hilly areas where the ground is loose and unstable, especially in areas where heavy rainfall occurred during previous tropical systems, including Hurricane Laura. Additionally, Hurricane Delta is likely to produce tornadoes, especially in southern Louisiana and southern Mississippi, over the coming days.

Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions over the coming days. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel 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.

Advice

Activate contingency plans in areas where officials forecast hurricane or tropical storm conditions. Heed all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high 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 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. Keep any necessary medications in a waterproof container.

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.