Louisiana communities beginning the huge task of clearing debris and repairing the damage inflicted by Hurricane Ida are facing the dispiriting prospect of weeks without electricity in the oppressive, late-summer heat.

Ida ravaged the region’s power grid, leaving all of New Orleans and hundreds of thousands of other Louisiana residents in the dark with no clear timeline on when the electricity would come back on. Some areas outside New Orleans also suffered major flooding and structure damage.

“I can’t tell you when the power is going to be restored. I can’t tell you when all the debris is going to be cleaned up and repairs made,” Gov. John Bel Edwards said Monday. “But what I can tell you is we are going to work hard every day to deliver as much assistance as we can.”

The storm was blamed for at least four deaths in Louisiana and Mississippi, including two people killed Monday night when seven vehicles plunged into a 20-foot-deep (6-meter-deep) hole near Lucedale, Mississippi, where a highway had collapsed after torrential rains.

On Monday, rescuers in boats, helicopters and high-water trucks brought more than 670 people in Louisiana trapped by floodwaters to safety. An additional 20 people were rescued in Mississippi. Crews planned to go door to door in hard-hit areas to make sure everyone got out safely.

Also stuck in New Orleans were tourists who didn’t get out before the storm. The airport canceled all incoming and outgoing commercial flights for a third day, saying the lack of power and water meant no air conditioning or restrooms.

Adding to the misery was the steamy weather. A heat advisory was issued for New Orleans and the rest of the region, with forecasters saying the combination of high temperatures and humidity could make it feel like 105 degrees Fahrenheit (41 degrees Celsius) on Tuesday and 106 on Wednesday.

Power crews rushed into the region. Louisiana’s governor said 25,000 utility workers were on the ground in the state to help restore electricity, with more on the way.

Still, his office described damage to the power grid as “catastrophic,” and power officials said it could be weeks before electricity is restored in some spots.

More than 1 million homes and businesses in Louisiana and Mississippi were left without power as Ida pushed through on Sunday with winds that reached 150 mph (240 kph). The wind speed tied it for the fifth-strongest hurricane ever to hit the mainland.