Hurricane Ida weakened to a tropical storm Monday after crashing into Louisiana and knocking out power to more than 1 million homes and businesses including the city of New Orleans.

Officials earlier warned of "life-threatening" floods. At least one person, a 60-year-old man, died in Ascension Parish after a tree fell on his home, authorities said.

Electric utilities reported that slightly more than 1 million homes and businesses were without power in Louisiana and another 100,000 in Mississippi. Entergy New Orleans, the main power utility in the city, with nearly 200,000 customers, said the entire city lost electricity early Sunday evening because of "catastrophic damage" to its transmission system. It said power wouldn't be restored Sunday night.

The National Hurricane Center said that the rain and storm surge has "resulted in catastrophic impacts along the southeast coast of Louisiana." It warned of dangerous storm surges and flash floods around southeastern Louisiana and southern Mississippi after Ida made landfall as one of the strongest storms in U.S. history. It also said tornadoes were possible into the evening from Mississippi to the western Florida Panhandle.

Now headed to Mississippi, the storm's winds stood at around 45 miles an hour as of 5 a.m. ET and the hurricane center warned that gusts could still cause damage as it continues to moves inland.

The hurricane’s high winds ripped roofs from buildings in New Orleans, scattered debris across the famed French Quarter, toppled large trees and brought on flooding in Grand Isle, Louisiana. In St. Rose, in greater New Orleans, video posted on social media showed two large boats crashing into each other.

Early Monday, local officials were preparing to survey the damage as the sun came up and teams got ready to head out to check on those who called for rescue throughout the night. Jefferson Parish President Cynthia Lee Sheng told "TODAY" that around 250 calls for rescue came in overnight.