One person has died and at least 27 people are being treated for carbon monoxide poisoning from portable generators.
Officials are reminding people to operate portable generators only outside, 20 feet away from homes, doors and windows. Not in carports, garages, basements.
To restore power, Entergy has "islanded" (disconnected) the City of New Orleans from the regional grid and started a local power plant. The transmission lines were toppled during the storm, but the cables were still connected to the terminals. Islanding the city makes sense, but I don't remember a power company islanding large parts of the grid before. Public officials are now saying it may be 30+ days to fully restore power.
Entergy has implemented restoration priority, which means hospitals, public safety and critical infrastructure will be restored first. Along with some incidental customers on the same circuits.
Customers out of service
Louisiana - 987,588
Mississippi - 31,516
Florida - 21,867
California - 21,339
Pennsylvania - 10,415
Reminder, Puerto Rico still has not fully recovered from hurricanes in 2017. Puerto Rico still has rolling blackouts. And yes, Puerto Rico is an island, so its electric grid is naturally an island.
The major wireless providers have activated their open roaming agreements, allowing customers to roam on any working infrastructure from other service providers. They are also waiving overages and many other feeds in the affected region. Check your service provider's website for details.
AT&T says 82 percent of its network in service in Louisiana.
First responders say the AT&T FIRSTNET failed (again) during the hurricane.
T-Mobile says 70 percent of its network in service in Louisiana.
Verizon says it has "gaps in coverage" but its network remains resilient. I don't know what that means.
I haven't found reports from cable companies in the region.