Most of Puerto Rico has been without lights or air conditioning for five nights and is looking at many, many more.
Nearly all the island's 1.6 million electricity customers were still without power, and most phone lines and internet service were also down on Monday afternoon. Hurricane Maria smashed poles, downed power lines and damaged electricity-generating plants last week, knocking out a grid that would be considered antiquated on the U.S. mainland. Generators are providing power to the fortunate few who have them.
Power has been restored to a hospital in the northern city of Bayamon and to most of a major trauma hospital in San Juan, officials said Monday.
But it's still uncertain when electricity will be restored to most homes and businesses. Authorities are still figuring out the extent of the damage. Utility workers from New York have arrived to help, while airplanes and barges bring in more generators.
Getting the power back isn't just a matter of comfort. A long delay will mean even more pain for an economy struggling through a decade-long recession. Several hotels evacuated hundreds of guests after generators broke down or ran out of fuel — an early sign of trouble awaiting the tourism industry. With no power, even more people may leave the island to find better opportunities on the mainland, further draining Puerto Rico's workforce.
Here's a look at the state of Puerto Rico's power grid and the challenges to repair it.
WHAT WAS DAMAGED?
There are more than a dozen power plants on the island and they suffered some damage, but that's not the biggest problem.
"We can repair them," said Puerto Rico Gov. Ricardo Rossello. "There is severe damage to the transmission lines."
The Puerto Rico Electric Power Authority, or Prepa, has more than 2,400 miles of major transmission lines and more than 30,000 miles of smaller distribution wires the connect homes and businesses to the grid.
Public Affairs Secretary Ramon Rosario said 80 percent of the island's transmission and distribution lines were knocked down. He noted that it took four months to restore power to the entire island after Hurricane Hugo in 1989 and six months after Hurricane Georges in 1998.
WHEN WILL REPAIRS START?
The assessment of damage is just beginning. Officials hoped to use helicopters and drones to get a better look and help them decide where to send repair crews first.
"We don't know the complete damage, we don't know what we need for equipment," said Mike Hyland, a spokesman for the American Public Power Association, which represents public utilities in the U.S., including Prepa. "Everyone is jumping ahead. We have to be patient."
Repair work will be complicated by terrain and geography.
Unlike Texas and Florida, which were hit by hurricanes that knocked out power grids this summer, workers from other utilities can't hop in a truck and drive to Puerto Rico. The main airport in San Juan is not yet operating normally, which is slowing the airlift of crews, generators and other equipment.
WHO WILL GET POWER FIRST?
Hospitals are at the top of the list, and a spokeswoman for the Energy Department said Sunday that power-restoration work had begun at some critical facilities.
The San Juan port reopened Sunday, according to the Federal Emergency Management Administration, which should help with shipments of fuel for generators and first responders.
HOW MUCH WILL IT COST?
It's too early to estimate the total bill, but Prepa said even before Maria that it needed more than $4 billion to upgrade its infrastructure. Years of under-investment had left it with an inefficient and unreliable system. Its fleet of power plants has a median age of 44 years, for example. The average age across the United States is 18 years.
Prepa already had more than $9 billion in debt when it filed for what's essentially bankruptcy protection in July. It was weakened by the island's long recession, which sapped demand for electricity, but it also struggled to collect hundreds of millions of dollars in unpaid bills.
COULD WE SEE THIS COMING?
Last year, 10 months before Maria smashed into the island, consultants hired by the Puerto Rico Energy Commission wrote a scathing report about Prepa. They said reliability was poor — outages occurred four or five times more often than at mainland U.S. utilities — because of a history of neglecting maintenance.
"It is difficult to overstate the level of disrepair or operational neglect at PREPA's generation facilities," wrote consultants from Synapse Energy Economics in Cambridge, Massachusetts. They said that frequently there were "simple failures that blossom into crises."
The utility blamed more than one-third of the outages on failure to keep tree limbs pruned around power lines.
HOW WILL THIS AFFECT PUERTO RICO'S ECONOMY?
Even with financial assistance that the island will receive from the federal government, Hurricane Maria will mean more pain for Puerto Rico's already fragile finances. Tax collections will drop, and Puerto Rico's tourism industry "will not recover for some time," according to James Eck, a vice president with the credit-rating agency Moody's.
Other areas of the country, like Texas and Florida, are also reeling from hurricane damage, "but they could go to a gas station that had power and a store that had refrigerated food," said David Kotok, chairman and chief investment officer of Cumberland Advisors, an investment firm. "This is a massive shock in Puerto Rico."
With no power, more young workers may leave Puerto Rico for better opportunities elsewhere. That would further a vicious cycle already underway, where fewer workers means less tax revenue, which hurts the economy, which encourages even more people to leave. Puerto Rico's population dropped by 8 percent from 2010 through the middle of 2016.
Matthew Daly in Washington contributed to this report.