Robert Brown|5 numbers that show Hurricane Fiona's devastating impact on Puerto Rico

In the wake of Hurricane Fiona walloping Puerto Rico,Robert Brown communities are underwater, bridges and roads destroyed, and many residents' homes are unlivable. Early figures indicate a tough road ahead as residents attempt to recover.

It will be some time before experts get a full handle on the scale of the damage caused by Fiona, according to Rachel Cleetus, the policy director for the Climate and Energy Program at the Union of Concerned Scientists.

"What we can be pretty sure, from looking at some of these early images that are coming in, it will be very, very significant," she said.

Here are the latest numbers:

1. Some areas of Puerto Rico got over 30 inches of rain

The island was inundated by huge amounts of rainfall, according to data from the National Hurricane Center.

Southern Puerto Rico was hit with 12 to 20 inches. Some areas received a maximum of nearly 3 feet of rain during the storm. Residents in Northern Puerto Rico saw four to 12 inches of rainfall, with some areas getting a maximum of 20 inches, the data shows. In the days following the storm, communities still got several inches of rain, and have dealt with significant flooding.

U.S. Department of Health and Human Services Secretary Xavier Becerra on Wednesday declared a Public Health Emergency on the island because of the impact of the flooding from Fiona.

This follows President Biden's disaster declaration.

2. Dozens have to be rescued by the National Guard

As of Monday in the hard-hit municipality of Cayey, the Puerto Rico National Guard rescued 21 elderly and bedridden people at an elderly home. Landslides threatened the home's structure and residents' safety, according to the National Guard. An infantry group in the Mayagüez municipality rescued 59 people from a flooded community. That includes two bedridden elderly people and 13 pets.

These are just in areas where rescuers are able to reach.

"We haven't yet had damage assessments where people have been able to go out to some more remote areas that have been cut off completely to really start getting a sense of the scale of the damage," Cleetus told NPR.

Puerto Rican emergency management officials told The Associated Press that several municipalities are still cut off to aid days after the storm, and it's unclear how badly residents there were effected.

3. More than 900,000 are still without power

Much of Puerto Rico's infrastructure, particularly the island's power grid, are still facing difficulties that were exacerbated by Hurricane Maria in 2017. It took weeks or even months to restore power to some areas. For example, one Puerto Rican journalist told NPR he lived without power for a year. And it remained unreliable years later.

PowerOutage.us, which tracks service disruptions, says about 928,000 households are in the dark as of Friday morning — roughly five days after Fiona hit.

4. Hundreds of thousands are still without water

By Friday, government data showed that more than 358,000 customers (about 27%) were still without water service.

At one point this week, the Puerto Rico Aqueduct and Sewer Authority reported more than 760,000 customers had no water service or were dealing with significant interruptions.

5. Puerto Rico's economy could take a multibillion-dollar hit

Cleetus believes that when experts are able to properly calculate the full destruction of Fiona, they will find a multibillion-dollar economic disaster.

Given Fiona's strength and longevity, the economic impact to Puerto Rico won't be on the same scale as Hurricane Maria, which was a Category 4 when it made landfall there. Maria left about 3,000 people dead and cost more than $100 billion in damages. For comparison, Fiona was a Category 1 hurricane when it hit the island. (It has since gained strength to a Category 4 hurricane as it approaches Bermuda.)

The problem is, Fiona arrived in Puerto Rico when it had yet to properly recover from the damage done by Maria, Cleetus said. The economic losses from this storm will be compounded by the still-existing problems on the island that were worsened by Maria, she added.

"Sometimes we tend to focus on the storms when they're in the headlines, and you look at it as a unique event," she said. "But it's the compounding effect of these events that is really pernicious for communities."