The total damage and economic loss from Hurricane Ida could reach $70 billion to $80 billion, according to an estimate from AccuWeather.

The fifth-largest hurricane to ever make landfall in the U.S. Ida — now downgraded to a tropical storm — has left more than a million residents and businesses without power, including the entire city of New Orleans. Officials expect the outages to last a week or longer, straining individuals and businesses as well as jeopardizing people’s health in the late-summer heat. 

New Orleans-based power company Entergy is sending out a crew of at least 20,000 workers, which it expects will take several days to assess the damage in New Orleans and southeast Louisiana. The storm took out all eight power transmission lines in the area along with some generating stations, and customers in the area could face “extended power outages lasting for weeks,” the company said.

The storm has also halted oil and gas production in the area, with roughly 90% of oil and gas production halted as the storm approached. That’s expected to boost the price of gasoline in coming weeks, analysts said.

Exxon Mobil said its Baton Rouge Fuels Terminal in Louisiana reopened operations Monday while its Hoover platform in the Gulf of Mexico suffered no storm damage, and crews are starting to resume normal operations.

Colonial Pipeline said late Monday that it expected to return two lines between Houston and Greensboro, North Carolina to service in the evening, pending successful completion of all restart protocols.

Meanwhile, Philips 66’s refinery in Belle Chasse, Louisiana, took on water and remained shut down as of late Monday, the company said. Its Gulf Coast lubricants plant in nearby Sulphur is reopening Tuesday. 

As Ida moves north, it is expected pass through areas already hit hard by tropical storms Fred and Henri, according to AccuWeather, noting in its analysis that parts of Mississippi and Tennessee will be “at serious risk of flooding.”  

“Even though Ida is no longer a Hurricane, its remnants as a significant tropical storm still will pose a very serious threat from torrential rains and flooding all the way up into the Appalachians and the mid-Atlantic states,” the weather service said. 

AccuWeather’s tally of the economic impact accounts for all direct and indirect costs of the storm, including both insured and uninsured losses; damage to structures and their contents and to cars; job and wage losses; business losses; travel disruption; and medical expenses. The estimate also includes long-term impact on affected industries, including tourism and oil and gas production

While the storm’s financial hit will be significant, it won’t approach the toll of Hurricane Katrina, which hit New Orleans on the same date 16 years ago and remains the costliest U.S. hurricane. Katrina killed more than 1,800 people and caused damage worth $176 billion. Both figures were exacerbated by failures of New Orleans’ levee systems, which have been strengthened in the intervening years. 

Ida has been blamed for four deaths, including two people who died in a highway collapse, a driver who drowned near New Orleans and a person hit by a falling tree near Baton Rouge.

While Ida was a stronger storm than Katrina at landfall, financial consultancy Boenning & Scattergood found that Ida’s wind field is smaller than Katrina’s, which likely narrows the area of catastrophic damage. The analysts estimated $10 billion in losses for the insurance industry, far less than the more than $90 billion from Katrina.

Hurricanes — known as cyclones in the Southern hemisphere — are the most destructive and deadliest natural disasters to hit the U.S. Climate change, which is worsened by human activities, is making them stronger and more destructive. Three major hurricanes have made landfall in southern Louisiana this year alone.

The Associated Press contributed reporting.