It’s been less than a week since Hurricane Maria tore through Puerto Rico, bisecting the entire island, bringing 150 mph winds and torrential rains to some of its most populated areas.

But the crisis in Puerto Rico, a US territory whose residents are citizens of the United States, is just beginning, and will likely last months or years.

Puerto Rico’s entire power grid was knocked offline during the storm. The New York Times reports it could be four to six months before power is restored on the island. That’s half a year relying on generators, half a year without air conditioning in the tropical climate, half a year where even the most basic tasks of modern life are made difficult. And remember: 3.4 million people live there.

Related Where you can donate to help with hurricane and earthquake relief and recovery

Making life even harder: Cell service is out on almost the entire island, and communications are generally strained. Thousands of people living in the mainland United States with relatives in Puerto Rico have yet to make contact. At least six people died during the storm, but this number could rise due to the fact that news is moving slowly on the communications-choked island.

Meanwhile, new crises keep forming in the wake of the storm. On Friday, the National Weather Service issued a dire warning about the Guajataca Dam in the Northwestern corner of Puerto Rico, which is reported to be near the point of breaking, threatening downstream areas with deadly floods. Seventy thousand people — enough to fill a small city — have been asked to evacuate areas that could be flooded by the nearly 11 billion gallons of water the dam holds back.

Puerto Rican officials believe the dam’s failure is imminent. “It could be tonight, it could be tomorrow, it could be in the next few days, but it’s very likely [the dam will break] soon,” Christina Villalba, a spokesperson with Puerto Rico’s emergency management agency, told Reuters.

Direct hits from hurricanes always cause damage. But Puerto Rico was especially vulnerable.

Relief efforts are underway: New York Gov. Andrew Cuomo led a flight to the island that brought 34,000 water bottles, 9,600 meals, and electrical generators to power hospitals and other relief centers. But this also illustrates one reason the recovery will be long and hard for Puerto Rico — it will need supplies and building material shipped from overseas.

Getting the power back on in Puerto Rico “will be daunting and expensive,” the New York Times explains. “Transformers, poles and power lines snake from coastal areas across hard-to-access mountains. In some cases, the poles have to be maneuvered in place with helicopters.”

Before Maria hit, around 60,000 people on the island were still without power from Hurricane Irma. And any power outage in Puerto Rico is a serious issue, as Vox’s Alexia Fernandez Campbell explains, because the government is broke. Its infrastructure is aging and in disrepair on a good day. And it can’t borrow money to fix these problems. Campbell writes:

It all comes down to money, and the government of Puerto Rico doesn't have it. The island, which is a US territory, filed for bankruptcy-like protection earlier this summer, and is in the process of restructuring its debt. Now the public utility company is in a severe state of financial distress, unable to modernize its system and facing a shortage of high-skilled workers. Even FEMA relief money that Congress will likely authorize will be of limited help in such an environment.

When it made landfall, Maria bisected the island from the Southeast to the Northwest. “It was as if a 50- to 60-mile-wide tornado raged across Puerto Rico, like a buzz saw,” Jeff Weber, a meteorologist with the National Center for Atmospheric Research, says. “It’s almost as strong as a hurricane can get in a direct hit.”

Here’s how you can donate to the relief efforts.