Hurricane Ida has reached Louisiana, the US state accompanied by winds of 150mph (240km/h) and a possibly “catastrophic” storm surge, the National Hurricane Center (NHC) says.
Thousands of people left the state when the warning about the storm came through, but by Sunday morning it was too late to leave.
State Governor John Bel Edwards said that this could be the worst hurricane ever to hit Louisiana since the 1950s.
The hurricane got all its strength over the warm waters of the Gulf of Mexico.
It was a category four hurricane on the five-step Saffir-Simpson scale – meaning it will cause severe damage to buildings, trees and power lines and made landfall near Port Fourchon, south of New Orleans.
At certain places the storm outpouring could be as high as 16ft (4.8m), potentially immersing parts of the low-lying shoreline.
The effect of climate change on the regularity of storms is still uncertain, but augmented sea surface temperatures warm the air above, making more energy available to cause hurricanes.
Therefore, they are expected to be more intense with more extreme rainfall.
Ida arrived on the 16th anniversary of Hurricane Katrina, in 2005. It was a category three storm that besieged New Orleans and killed more than 1,800 people.
The US National Weather Service (NWS) warned New Orleans residents to shelter in place immediately if they had not already done so.
“Go to an interior room or a small room with no windows. Stay put during this time,” the NWS tweeted.
Moreover, Louisiana hospitals are now under pressure from Covid-19. The state has the third-highest rate of infections in the US.
Generally, hospitals in the foretold path of the storm would be evacuated, but this time there are few beds available, even at facilities further inland.
“We don’t have any place to bring those patients. Not in state, not out of state,” Mr Edwards said.