Hurricane (Typhoon) — Lower Terrebonne, Louisiana

2021-08-29 to 2021-08-30 · Lower Terrebonne, Louisiana

Event narrative

The parish suffered extreme impacts as the eyewall raked the eastern half of the parish as it moved inland. There was widespread catastrophic damage to structures throughout the parish and both of the parish's hospitals were severely damaged. An estimated 60% of homes in the parish's bayou communities were deemed unsafe for habitation, with many losing their roof structures removed, collapsed walls, or trees falling through them. The LUMCON Marine Center in Cocodrie suffered substantial damage, and several public buildings including 2 fire departments also suffered major structural damage. Most power poles were snapped or damaged. Nearly every road in the parish was blocked by downed trees, utility poles, or other debris. During the storm, 2 offshore vessels broke free, crashing into the Bouquet Bridge near Dulac. The entire parish was left without power and most without natural gas or water service following the storm. The strong winds and current caused damage to the parish's main floodgate on the Houma Navigational Canal which was designed to withstand stronger forces from the south.

Wider weather episode

The ninth named storm, fourth hurricane, and second major hurricane of the 2021 Atlantic hurricane season, Ida originated from a tropical wave in the Caribbean Sea on August 23rd. On August 26th, the wave developed into a tropical depression, which organized further and became Tropical Storm Ida later that day, near Grand Cayman. On a northwestward track, Ida intensified into a hurricane on August 27, just before moving over western Cuba. A day later, the hurricane underwent rapid intensification over the Gulf of Mexico as it passed over a warm core eddy and reached major hurricane strength. It was just under 72 hours from tropical depression formation to category 4 strength with 150 mph winds. Ida remained at its peak intensity of 150 mph winds and a minimum central pressure of 929 millibars as it made landfall near Port Fourchon midday on August 29th. It didn't weaken to a tropical storm until it reached near the Louisiana/Mississippi border.

Ida produced extensive to catastrophic damage across southeast Louisiana. On Grand Isle, around 40% of the structures were destroyed and the island was uninhabitable. Near 75% of the structures in Lafourche Parish were damaged or destroyed and likely similar numbers in Terrebonne Parish. 100+ mph wind gusts reached as far inland as Interstate 12. These winds damaged more than 30,000 poles, over 36,000 spans of wire and nearly 6,000 transformers. Of those more than 30,000 Louisiana poles, nearly 80% of those broken or damaged are from the most heavily impacted areas.

In total, the number of damaged or destroyed poles from Ida is more than hurricanes Katrina, Ike, Delta and Zeta combined. Due to major destruction to the power grid across the region, over 1 million customers were without power after landfall. Some of those power outages near the Louisiana coast lasted for around 4 weeks.

The Louisiana Department of Health reported 3 direct fatalities and 28 indirect fatalities. Excessive heat and carbon monoxide poisoning were the most common causes of death. Indirect injuries associated with Ida: 351 heat-related, 183 carbon monoxide exposure, and 3 electrocutions. Storm surge ranged from a few feet to 10 to 15 feet. Hurricane Ida caused approximately $30 billion worth of damage.

Source: NOAA Storm Events Database, event_id 979237. Narrative written by the NWS forecast office that issued the report.