It’s been more than six weeks since hurricane Maria made landfall in Puerto Rico, and life in the island is still filled with uncertainty: How many people died? When will power come back? How big will the storm’s impact be on the economy?

In this series, Quartz is examining questions Puerto Ricans are navigating. Here’s the second installment, on Puerto Ricans who left the island after Maria.

San Juan, Puerto Rico

Last week, José Luis Robles, a 25-year-old small auto shop owner from central Puerto Rico, boarded a plane headed to Pennsylvania. Today he has a job at a warehouse in Harrisburg and plans to send for his wife Keishla Pagán and two-year-old daughter Keirelys by the end of the year.

Robles is one of 100,000 Puerto Ricans who have left the island in the aftermath of hurricane Maria, according to official estimates disclosed at a congressional hearing on Tuesday. That’s equivalent to around 1,800 residents a day since the storm hit the island on Sept. 20, and more than the total number of Puerto Ricans who flew out in all of 2015 (link in Spanish,) the latest year for which data is available.

It’s understandable why they’re are flocking to the mainland. Nearly 60% of the island’s power generation is still offline. Water service hasn’t been fully restored. Communications remain spotty. The slow return to normalcy is crippling large swaths of Puerto Rico’s economy. “The pros are too many compared to the cons,” said Robles, whose home was rendered uninhabitable by the hurricane.

The longer the service outages last, the more people will leave, and the more difficult it will be for the island to recover.

Puerto Rico had been stuck in that vicious cycle even before the storm’s arrival. A long economic recession led to a mass exodus over the past decade. From 2006 to 2015, more than 400,000 Puerto Ricans moved to the mainland, reducing the island’s population to 3.4 million.

Fewer residents equal fewer customers for local businesses. That means fewer tax collections for the government, and less money to spend on infrastructure and other public goods that promote economic growth. Maria’s aftermath exacerbates that damaging chain of events.

Uncertainty of how many will leave for good is also dampening economic activity. Local firms, including the island’s bankrupt public electric utility, need to calculate how many clients they will have in order to plan for the future. “We’re in limbo,” said Raúl Sierra, owner of a San Juan craft-brew bar called El Tap.

Other members of Robles’s family could follow him to the mainland in coming months. His wife’s sister, Jenilie Pagán, 23, was flying to the US the same day he left. It was a quick trip to drop off a family friend before returning to her job as a cafeteria supervisor in a San Juan suburb—and an opportunity to explore whether she might be better off leaving the island, she said.