Hurricane Ida weakens to tropical storm after knocking out power in New Orleans

Deadly Hurricane Ida, now a strong tropical storm, was bringing heavy rains, "dangerous" flash flooding, storm surge and extreme winds as it moved northward across southeastern Louisiana and across Mississippi on Monday morning.

The latest: Ida weakened to a tropical storm early Monday, but remained formidable with flash flooding, damaging winds and isolated tornadoes in its arsenal. Flood watches are in effect all the way to the Mid-Atlantic.

Get market news worthy of your time with Axios Markets. Subscribe for free.

• The storm left more than 1 million people without power on Sunday night and into Monday morning, including the entire city of New Orleans.

• The National Weather Service declared flash flood emergencies Sunday night for several Louisiana regions overnight — including LaPlace, in the New Orleans metropolitan area, where the NWS received "multiple reports of significant flooding" late Sunday.

• Sheriff's deputies in Louisiana responding to reports of a tree falling on a person in Prairieville, south of Baton Rouge, confirmed the first death from the storm on Sunday night.

State of play: As of 5 a.m. ET, Ida's maximum sustained winds had dropped to 60 mph, as it was located some 50 miles north-northeast of Baton Rouge, Louisiana according to the National Hurricane Center. It was crawling northward at 8 mph.

Category 4 Hurricane Ida after making its second landfall in Louisiana on Aug. 29, 2021. (CIRA/RAMMB)

The big picture: Ida made landfall in Port Fourchon, Louisiana, as an "extremely dangerous" Category 4 storm on Sunday afternoon, with maximum sustained winds of 150 mph. It's one of the strongest hurricanes to hit the state on record.

• It weakened in the evening to a Category 3 hurricane before weakening again, but it still caused devastation and widespread power outages across southern Louisiana.

• The only power in New Orleans was coming from generators overnight. At least one energy provider warned outages could persist for weeks.

• Emergency medical services were suspended in New Orleans due to dangerous winds, New Orleans EMS tweeted. Wind gusts of up to 90 mph were reported in the city on Sunday.

Of note: "Catastrophic" wind damage was expected where the core of the storm was passing, and extremely dangerous winds were spreading inland throughout the day. A weather station near Dulac, Louisiana, south of Houma, reported a wind gust to 138 mph about 4 p.m.

• The NWS told residents to move to interior rooms of their homes and not to go outside for the next 24 hours, and to treat the winds "as if a tornado was approaching."

• The agency noted that four to eight inches of rain had fallen in southeastern Louisiana, with about the same amount expected to add to that rainfall.

What's next: Ida was expected to continue to weaken as it moved inland and was forecast to become a tropical storm by Monday morning.

• "Although Ida has been inland over southeastern Louisiana for several hours, it is still a very well organized hurricane," the National Hurricane Center noted.

• "[D]amaging winds, especially in gusts, are expected to spread further inland over southeastern Louisiana and southwestern Mississippi through Monday morning."

What to watch: Numerous oil and gas facilities and chemical plants were in the path of some of the strongest winds and storm surge, including the strategic Port Fourchon, which is integral to the Gulf of Mexico's oil and gas production.

• Damage to infrastructure there and upriver, between New Orleans and Baton Rouge, could lead to environmental hazards and delays in resuming oil and gas production in the Gulf.

Context: The rapid intensification, which exceeded forecasts, was due to extremely warm ocean waters and ideal conditions in the atmosphere as well. The Gulf of Mexico served as gasoline thrown onto the fire of the storm.

• Human-caused climate change, by warming air and ocean temperatures, is leading to both stronger and wetter hurricanes, and also more storms that rapidly intensify.

• The Gulf of Mexico has seen a recent trend of storms like Ida, which strengthen right up through landfall, whereas this used to be extremely uncommon (even Hurricane Katrina weakened as it neared land).

Go deeper: Meteorologists ahead of Hurricane Ida arrival: "We can't bear to see this on satellite"

Editor's note: This article has been updated with new details throughout.

More from Axios: Sign up to get the latest market trends with Axios Markets. Subscribe for free