A nursing home in San Juan made desperate pleas for diesel as its power generator ran low. An elderly man was carried out on a stretcher after going a week without dialysis. Children wearing nothing but diapers camped out on balconies to stay cool.

This is Puerto Rico's hottest time of the year — and next to nobody has air conditioning. Hurricane Maria, which smashed into the island five days ago and devastated the power grid run by Puerto Rico Electric Power Authority, couldn't have struck at a worse time.

Crews have descended on the island to begin the arduous task of resurrecting what was an already aging and long-neglected system. But that will take weeks, if not months — meaning more sleepless summer nights for those like Juan Bautista Gonzalez.

"It's brutal," said Gonzalez, 36, a carpenter sitting on a stoop in Old San Juan, rubbing his forehead in frustration. "No one can sleep. I spend all night tossing and turning. This is chaos."

The destruction that Maria exacted on Puerto Rico's fragile electricity system when it slammed ashore as a Category 4 storm is unprecedented — not just for the island but for all of the U.S. Every part of the grid was damaged.

In the 32 years that National Guard Brig. Gen. Wendul G. Hagler II has served, he said, "It's about as large a scale damage as I have ever seen." Hagler had visited the U.S. Virgin Islands just before Maria hit.

For an indication of how long it will take for Puerto Rico to rebuild the system, Gov. Ricardo Rossello points to Hurricane Hugo, a powerful storm that ravaged the region in 1989. Some had electricity within two months of Hugo. Others spent six months waiting. "It's a gradual thing," Rossello told reporters Sunday. "You have to be careful not to alarm people."

The lack of phone and internet access isn't helping. Puerto Ricans pulled over along highways over the weekend to take advantage of the rare spots where cellular service was available. They called into the few radio stations still working in an attempt to connect with relatives.

To make matters worse, Puerto Rico's power plants are clustered along the island's south coast, a hard-to-reach region that was left exposed to all of Maria's wrath, said Kenneth Buell, a U.S. Energy Department official who is helping lead the federal response. A chain of high-voltage lines across the island's mountainous middle connect those plants to cities in the north.

Puerto Rico's rich hydropower resources have also taken a hit. On Friday, the National Weather Service pleaded for people to evacuate an area in the northwest corner of the island after a dam failed. The rest of the dam is still at risk of bursting.

On Monday, the U.S. ramped up its response to the humanitarian crisis. Federal workers supplied diesel to fuel generators at hospitals and delivered food and water to hard-hit communities across the island. Cargo flights are bringing in additional supplies, and barges loaded with more goods are starting to arrive in the island's ports.