National

Ominous forecasts about the impact of climate change serve as the backdrop for the world — led by U.S. lawmakers and companies — to debate big action on the problem, which could upend energy systems and our way of life.

Energy & Environment

Tropical Storm Fiona is expected to become a hurricane and could dump as much as 20 inches of rain on Puerto Rico beginning Saturday, the National Hurricane Center warned. 

Driving the news: The meteorological agency issued a hurricane warning for the U.S. territory, where the impending flooding and high winds could imperil the island's power grid, which is still recovering from 2017's Hurricane Maria.

Catch up fast: Fiona has already dumped 17 inches of rain on the island of Guadeloupe and brought significant flooding to some eastern Caribbean islands. 

As of Saturday morning, the tropical storm was located about 130 miles southeast of St. Croix and was moving west. It’s on pace to pass near or over Puerto Rico on Sunday night. 

A Saturday afternoon updated from the NHC revealed no significant chances in the forecast for Puerto Rico, though the agency stressed the likelihood of "life threatening" flooding occurring as a result of the storm. The NHC also said the storm is expected to be a hurricane when it makes landfall sometime on Sunday.

 Data: National Hurricane Center; Map: Jared Whalen/Axios 

Threat level: Forecasters are calling for 12 to 16 inches to fall in Puerto Rico with the potential for as many as 20 inches, particularly across eastern and southern swaths of the island. 

A hurricane watch is in effect for the southern coast of the Dominican Republic from Cabo Engano westward to Cabo Caucedo and its northern coast, from Cabo Engano westward to Puerto Plata. The island nation is forecast to get four to eight inches of rain, with up to a foot possible along its eastern coast. 

The U.S. Virgin Islands, also under a hurricane watch as of Saturday morning, are expected to receive four to six inches, with as much as 10 inches of rain possible.

The deluge could produce flash and urban flooding, as well as mudslides along higher terrain, particularly in southern and eastern Puerto Rico and the eastern Dominican Republic. On the nearby island of Guadeloupe, 19.85 inches of rain has fallen since Fiona arrived. 

Our thought bubble: From Axios’ Andrew Freedman: The National Hurricane Center raised the possibility of faster intensification prior to the storm’s arrival in Puerto Rico on Sunday, so it’s possible the storm could hit as a stronger Category 1 or even a Category 2 storm, depending on its development.

Once the storm emerges over the southwestern Atlantic, it is likely to further intensify, and appears destined to curve out to sea, away from the East Coast. However, the ultimate track is still subject to considerable uncertainty, so the East Coast from Florida to the Carolinas in particular should keep a close watch.

Editor's note: This story has been updated with additional forecast information from the National Hurricane Center. 

Tropical Storm Fiona prompts hurricane warning for Puerto Rico

The impending flooding and high winds could imperil the island's fragile power grid.

Puerto Rico

Vitals

Axios Vitals

Health systems are increasingly responding to the threat of climate change with commitments to cut back their own carbon footprint.

Why it matters: Health care is a massive global industry, and shrinking its carbon footprint could go a long way toward reducing carbon emissions.

Health care is responsible for about 4.6% of global carbon emissions, and in the U.S., the industry is responsible for 8.5% of greenhouse gas emissions.  

"To put that in perspective, if health care was a country, it would be the fifth-largest emitter in the world," Gary Cohen, president and founder of Health Care Without Harm, a group that focuses on reducing health care's carbon footprint, tells Axios.

Between the lines: The climate impact includes the direct emissions the health systems produce from the energy they use to power their buildings, plus the emissions from all the technology within them and the transportation of their hospital fleets and their massive workforces, Cohen said.

It also includes the anesthetic gases used in operating rooms that are ultimately vented into the atmosphere, the products they source in their complex supply chains, and even the companies supported with their investment portfolios.

What they're saying: "Given that health care is the one sector of our economy that has healing as its mission, that is underpinned by the Hippocratic oath to 'first do no harm,' we believe they have more responsibility than anyone else to model this transition away from fossil fuels and toxic chemicals," Cohen said. 

What's happening: But U.S. health systems' willingness to make commitments to reduce and offset their own global emissions still varies widely, said John Balbus, interim director of the year-old Department of Health and Human Services' Office of Climate Change and Health Equity. (Congress has not yet funded the office.)

"A fraction, a sliver, of the nation's private health systems have joined our climate pledge," he said, referring to the HHS's call for pledges by health systems to lower their greenhouse gas emissions and build more climate-resilient infrastructure. 

The White House and HHS are seeking pledges through October to recognize in an announcement timed with the United Nations Climate Change Conference in November. 

Zoom in: Balbus pointed to health care giants like Kaiser Permanente and Providence, which committed to a goal of reducing emissions by 50% by 2030 and achieving net zero emissions by 2050.

Already, Kaiser says it became carbon neutral in 2020 by purchasing clean energy and carbon offsets, drastically cutting emissions from anesthetic agents, and improving energy and water efficiency within its buildings.

Providence is pushing to become carbon negative by 2030, cutting emissions through renewable energy use, reductions in business travel and improved purchasing.

The health systems that are getting engaged see the direct connection to their core work, Seema Wadhwa, executive director of environmental stewardship for Kaiser Permanente, tells Axios. 

"As a society, we're seeing the impacts more. Climate change is no longer something that's happening in the future. Climate change is happening now," she said. 

There's also a recognition of how addressing climate vulnerabilities overlaps with existing efforts to address health concerns related to social determinants of health, said Elizabeth Baca, managing partner at Deloitte.

"It's an excellent opportunity to start to say, '[What] are the things in our different markets that are having the biggest impact? Who are the communities that are most vulnerable, and how can we plan for that?'" Baca said. "A lot of that work already happens, but it's just making those links on the climate side."

The bottom line: Focusing on health care's contribution to climate change isn't just a nice-to-have anymore. It's becoming an expectation.

Cutting health care's carbon footprint

Focusing on health care's contribution to climate change isn't just a nice-to-have anymore.

Illustration of a gloved hand cutting into a chunk of coal with a scalpel.

Climate truths

Climate Truths

The U.S. faces a range of health care flashpoints — unaffordable drugs, opioids, vaping — as we debate whether to adopt universal care. For now, the Affordable Care Act is the law of the land, but Republicans want to issue it a final death blow.

Health

Generate

Axios Generate

Climate anxiety is an increasingly accepted phenomenon that many psychologists and therapists are tailoring their practices to treat.

The big picture: The symptoms are especially prevalent among young people, and while it's not treated as an official clinical diagnosis, it can be debilitating at times, mental health professionals tell Axios. 

The experience of climate anxiety, referred to more broadly as "ecoanxiety," can be life-altering and distinct from other anxiety-provoking periods in someone's life, said psychotherapist Caroline Hickman, who is based in Bath in the U.K. 

Zoom in: Hickman was the lead author of a broad study on climate anxiety and its effects on young people around the world that was published in The Lancet late last year. 

That study of 10,000 people between ages 16 and 25 in 10 countries found greater levels of concern and more acute distress associated with climate change than she and her colleagues expected, Hickman said. 

For Hickman, the cognitive impacts of climate anxiety, particularly on young people, is distinctive since it affects how people imagine themselves in the future.  

"This is a level of horror and dread and distress I have not encountered before," Hickman said, noting that a lot of the negative emotions stem from the lack of action on the part of those in positions of power.

The intrigue: Distress also is the result of the lack of a light at the end of the tunnel, since climate change will be a lifelong challenge. 

Despite this, climate anxiety should not be classified as a mental illness and included in the Diagnostic and Statistical Manual of Mental Disorders (DSM), Hickman said. 

"It's a sign of mental health, not mental illness," she said, noting that worrying about climate change is a rational response. "But the suffering needs to be legitimized and understood."

Other mental health professionals agreed that climate anxiety should not be an official diagnosis in the DSM, since that could be a slippery slope to adding every anxiety trigger to the book.

Those suffering from climate anxiety may be diagnosed with broader anxiety-related disorders such as generalized anxiety disorder or depression.

Yes, but: Mental health professionals do think climate anxiety is a real and increasingly prevalent challenge, particularly as the impacts of global warming become more severe and pervasive. 

Thomas Doherty, a Portland, Oregon-based psychologist who specializes in ecoanxiety and wrote one of the earliest papers on the topic, said there are aspects that make this problem unique, but a DSM listing isn't appropriate. 

"There aren't specialized diagnoses for every life problem," he said. "There isn't unemployment depression or relationship breakup depression. ... There's anxiety, and there's a context."

Between the lines: The Lancet study found that about 60% of respondents were very or extremely worried about climate change.

More than 45% of respondents said their climate change-related feelings hurt their daily life and functioning. Levels of concern were high in vulnerable nations like the Philippines and developed nations alike.

According to Hickman, younger people are angry at older generations and those in power for not acting sooner and more boldly based on the scientific evidence of human-caused climate change. 

What's next: Mental health professionals have much they need to learn from climate anxiety sufferers. "There are still lots of questions about the different aspects of the emotional response to climate change," Susan Clayton, a psychology professor at the College of Wooster in Ohio, told Axios via email.  

The bottom line: A focus of therapy for climate anxiety sufferers is to help people navigate their feelings and eventually lead fuller lives, both Hickman and Doherty said. 

"The goal, ultimately, is to help us cope with climate change as a lifelong thing. It's going to be a part of all of our lives and into our children and grandchildren's lives," Doherty said.

If you need help for climate anxiety, the Climate Psychology Network and the Climate Psychiatry Alliance can connect you with a mental health professional who specializes in this area.

Feeling anxious about climate change? You're not alone

Young people in particular are feeling despair over climate change and the lack of government action.

Climate change is scrambling the way we fight infectious diseases and adding a stealthy public health threat to the heat waves, droughts, wildfires and other physically observable hazards.

By the numbers: In a study of 375 infectious diseases, 58% have at some point been aggravated by climatic hazards, researchers wrote last month in the scientific journal Nature Climate Change.

The threat isn't confined to microbes but includes allergens that can trigger asthma, skin and respiratory illness. 

Driving the news: Extreme weather events and changes in land cover disrupt habitats and redistribute mosquitoes, ticks, fleas, mammals and birds that have been connected to outbreaks of conditions like dengue, chikungunya, Lyme disease and West Nile virus.

"We need to stop thinking about it as something that affects forests and resources and understand that it affects our health," said Erik Franklin, co-author of the Nature study and an associate research professor at the University of Hawaii. 

Lyme disease is the most common vector-borne disease in the U.S., with climate change increasing the range of tick habitats. Northern states like New Hampshire, Vermont and Maine have seen the biggest increase in reported cases since the 1990s, per the National Association of County and City Health Officials.

More frequent hurricanes and prolonged rainy seasons also are bringing mosquito-borne illnesses like dengue and Zika virus to new places, the group said.

Gulf Coast states are increasingly vulnerable to parasite-driven rare tropical diseases like Chagas disease that disproportionately hit poor populations.

Yes, but: Researchers have to consider other factors such as population growth or the increase in international travel, both of which can stoke disease spread, said William Schaffner, medical director of the National Foundation for Infectious Diseases.

Zoom in: Some states are trying to be proactive. Colorado's Department of Public Health and Environment not only warns the public about hazards like West Nile virus, but tracks health conditions related to climate change and is trying to regulate greenhouse gas emissions.

Elsewhere, the Arizona Department of Health Services is evaluating the climate's effects on Valley fever and West Nile virus, but mainly focuses on prevention and surveillance.

Health officials who deal with infectious diseases should be focusing on both adapting to current risks from climate change and mitigating them, Katherine Catalano, deputy director of the American Public Health Association's Center for Climate, Health and Equity, tells Axios.

What we're watching: The COVID-19 pandemic may have slowed some disease spread through masking and social distancing. There's concern among some public health and infectious diseases experts that the relaxation of those precautions now could set up a disease resurgence in communities that aren't prepared.

Climate change alters battle against infectious diseases

It disrupts habitats and redistributes insects, mammals and birds that spread diseases.

Illustration of a petri dish surrounded by various blocks of color, grids, and measurements

The combination of extreme heat and air pollution is extremely lethal, and this noxious mix is likely to become more common as global warming worsens.

The big picture: It has long been known that particulate pollution emitted from car tailpipes, factories and power plants can aggravate chronic health problems and prove deadly. Add extreme heat, and the threat is especially dangerous.

Particulate matter refers to tiny airborne particles, including PM2.5, so named since it is 2.5 microns in length. This is about the width of a human hair.

In addition to cars and factories, wildfire smoke also emits such pollution.

According to a study published in June in the American Journal of Respiratory and Critical Care Medicine, co-exposure to heat extremes and particulate pollution is likely to become more frequent due to human-caused climate change. 

Other studies have also found harmful effects from wildfire smoke, which has become a growing problem in the West during the past decade. 

This week, smoke from multiple nearby wildfires prompted the National Weather Service to warn residents of large parts of Oregon, Washington, Montana and Wyoming to "[s]tay inside if possible. Keep windows and doors closed."

"If it's too hot, run air conditioning on recirculate or consider moving to a cooler location," the Sept. 12 warning stated.

Zoom in: The June study found that co-exposure to both extreme heat and air pollution at the same time "had a greater mortality effect" than if you just added their effects together, according to Mostafijur Rahman, the paper's lead author and a postdoctoral fellow at the Keck School of Medicine at the University of Southern California. 

"During the top 1% of hottest and most polluted days, [mortality] risk increased by 21%," the study found, Rahman told Axios via email. 

Hot days do not automatically have higher amounts of harmful particulate pollution, he said, but wildfires producing hazardous air quality tend to take place on the hottest days.

For example, several large, fast-moving blazes, such as the Mosquito Fire, grew in size across the West during the recent record-breaking heat wave. Air quality across California and in the Pacific Northwest deteriorated soon thereafter, in the middle of the worst September heat wave the region had ever experienced. 

How it works: "Older adults may be more susceptible to effects of extreme heat and air pollution exposure, in part because this stress comes on top of age-related chronic health conditions like heart disease, high blood pressure, diabetes or chronic lung disease," Rahman said. 

In addition, older adults may have a harder time getting to cooling centers if the shelters are located in the hottest parts of a community.

According to the study, the excess risk of mortality for extreme heat and pollution exposure among those over 75 years of age was 36.2%, compared to just 8.5% for those age 75 or below. 

Other research shows that children are particularly at risk from smoke-related health effects as well, with higher asthma rates and other ailments resulting from prolonged exposure.

Some cities are taking action to try to reduce the impact of air pollutants.

Phoenix, which currently has a visibility rating of good or excellent on only 70-80% of days, has set a goal to improve the air quality to good or excellent at least 90% of the time by 2050, Jessica Boehm of Axios Phoenix writes.

In June, the city adopted a transportation electrification plan that aims to get to 280,000 electric vehicles on Phoenix roads by 2030. This includes the electrification of the city's fleet and the installation of at least 500 public charging stations in the next decade.

Minneapolis has adopted "green zones" aimed at improving air quality and other environmental pollution issues in low-income neighborhoods, Torey Van Oot of Axios Twin Cities reports.

But activists and some people involved in the project say the initiative has yet to have its intended impact and that more changes are needed.

What's next: Rahman suggested that a special alert be developed for use during co-occurring heat and PM2.5 extremes. 

Governments are already experimenting with new ways to warn residents of heat risks, including a new system being developed in California.

The deadly mix of extreme heat and air pollution

The noxious mix is likely to become more common as global warming worsens.

Illustration of patients' hands, smokestacks, and abstract shapes. 

Heat-related deaths in Washington, 2010–2022

Data: Washington State Department of Health; Chart: Kavya Beheraj/Axios

A 2021 heat wave that killed at least 157 people in Washington state drove home why even regions accustomed to fresh air and moderate temperatures need to calibrate their public health efforts to confront extreme climate events.

Why it matters: The dual threats of extreme heat and smoke from wildfires can be fatal in places where many households lack air conditioning, or they could worsen chronic heart and lung diseases. 

But mitigation strategies have to account for a complex stew of factors, from social determinants of health like income and health literacy to communications systems capable of reaching those most at risk.

How it works: King County, one of three counties in the Seattle area, undertook a heat mapping project to identify areas with hard landscapes and less shade that hold heat longer to help guide decisions like where to open cooling centers.

The public health department established temperature thresholds at which point communities would open cooling centers.

Emergency management officials plan to send push alerts to landlines and cellphones ahead of extreme weather events, urging recipients to seek out a cooling center and to check in on vulnerable neighbors or family members.

"Maybe that will get people to start to understand that heat here in the Pacific Northwest is something they need to take seriously and is a killer," Brendan McCluskey, emergency management director at King County, tells Axios.

The officials also plan to apply for FEMA grants to help them buy heat pumps or air conditioners for residents.

Community organizations are stepping up in other parts of the state where local governments aren't coordinating planning.

In Spokane, Gonzaga University is using a National Oceanic and Atmospheric Administration grant to produce maps pinpointing heat islands and the most vulnerable neighborhoods, Brian Henning, director and founder of the Gonzaga Center for Climate, Society, and the Environment, tells Axios.

The Gonzaga team is also polling residents to find out precisely how many homes have air conditioning — data that can help the team create a heat action plan that the city can adopt.

In a state where the average high temperature peaks at 78°, just 53% of households used air conditioning in 2020, per a report by the U.S. Energy Information Administration. 

The big picture: State government efforts are increasingly focused on the threats climate change poses, with lawmakers approving more than $600 million through 2023 to reduce the emission of greenhouse gases.

The Department of Health can direct funding to local health departments to work on climate change and heat plans, as well as help local partners coordinate efforts.

Plans also call for longer-term changes like planting more trees and protecting areas from wildfires.

The Department of Natural Resources is running a pilot program in central and eastern Washington communities that are vulnerable to wildfires to make sure residents are signed up for emergency messaging and know what to do in the event of a fire or unhealthy air.

The efforts track, in some ways, with those in states like California that are facing increasingly catastrophic wildfire seasons. Mitigation plans there include encouraging people to wear N95 masks, install high-efficiency air filters and use air cleaners to reduce indoor particle levels.

The other side: Relying on solutions like air conditioning and purifiers puts the electrical grid in jeopardy, and some experts think they can't be the sole solution.

"If you have built your infrastructure dependent on electricity, and there's a power outage during more extreme events, you kind of set yourself up for a catastrophic event," said Claire Richards, an assistant professor at Washington State University College of Nursing and a member of the Washington Physicians for Social Responsibility Climate Action Task Force.

How the Pacific Northwest is combatting heat and smoke

The dual threats can be fatal in places where many households lack air conditioning.

The world is facing a climate change-fueled health crisis — from increased emergency department visits due to heatstroke, exacerbated asthma and even heart attacks to injuries and illness linked to severe storms. 

Why it matters: The growing threats to human health only promise to get more complex and expensive, and health systems have to make major changes to how they prepare for those threats, experts say. 

They're already estimated to exceed $800 billion a year in increased health costs.

"It's challenging because this is happening fast," Beth Schenk, executive director of environmental stewardship for Washington state-based Providence health system, tells Axios.

Last summer, the health system found itself in the center of a "shocking" heat wave in the Pacific Northwest at the same time that its workforce was already stretched thin due to COVID surges. 

The extreme heat stressed its buildings' cooling systems and forced the health system to reduce services in some cases even as its emergency rooms were filling due to heat-related illnesses, she said. 

"The requirements for your hospitals are to be appropriate for your climatic conditions. Well, our climatic conditions when we built those hospitals were not for 116 degrees," she said.

"That has certainly colored how we're planning now in our hazard vulnerability assessments, in our resiliency building, to be prepared for that again. It seems inevitable," she said.

Zoom in: During California's record-breaking heat event earlier this month, Kaiser Permanente switched to generators for power at its individual facilities to help reduce the stress on the state's electric grid, said Ramé Hemstreet, Kaiser Permanente's chief sustainable resources officer.

The goal was to ensure that more individuals in the community kept their power, including their cooling units.

"It highlights the fact we need to think about resiliency more broadly," said Hemstreet. The health system already generates about 28% of its energy onsite but is investing in more microgrid and solar fuel cells moving forward, Hemstreet said.

The big picture: The World Health Organization (WHO) calls climate change "the single biggest health threat facing humanity."

Climate change has also been linked to increased risks for kidney disease, obesity and diabetes, injuries, the transmission of infectious diseases, some cancers and poorer mental health.

What they're saying: "We are learning more and more that the combustion of fossil fuels is contributing to a massive epidemic of chronic disease around the world that dwarfs AIDS, malaria and tuberculosis combined," said Gary Cohen, president and founder of Health Care Without Harm, a group that focuses on reducing health care's carbon footprint.

There's a growing recognition among U.S. health systems that the threats from climate change will have a major impact on their operations.

"A lot of health care systems have started to grapple with the direct physical risks to their own facilities," said Brodie Boland, a leader in McKinsey's work on climate risk in the real estate and infrastructure sectors. 

Between the lines: Equity is central to the discussion about the health impacts of climate change.

"Climate change is impacting everybody. But it's not impacting everybody in the same way," said Seema Wadhwa, who is Kaiser Permanente's executive director of environmental stewardship.

For instance, older individuals and those who are immunocompromised are more vulnerable to the impacts of high temperatures and poor air quality.

Those individuals who depend on insulin or dialysis could be at greater risk in the event of a power outage or blockages to transportation. Some communities face greater threats than others.

What to watch: Community resiliency needs to become a far bigger focus as the climate changes, experts said.

"A hospital can do what it can from a backup generator and asset hardening perspective, but if the city around it has been severely damaged, there's only so much you can do," Boland said.

In one example, Providence said its population health team realized during last year's heat emergency that it was sitting on a massive amount of valuable information in its electronic health record that could help its response.

That EHR data helped them reach out directly to individuals at greater risk of health complications due to the heat and get them to places with cooling or air filtration and ensure they had access to medications, Schenk said.

The climate-driven health crisis

The threats to human health only promise to get more complex and expensive.

Illustrated collage of a body xray with pain points highlighted. 

Good afternoon, and welcome to our Climate Truths Deep Dive series. Today we're exploring the health care impact of climate change, and how the health care industry and emergency management officials are responding.

Axios Climate Truths: New health crisis

The  impact of climate change on our health.

Illustration of the earth with a stethoscope over it surrounded by red crosses and blocks of color

Japan is urging hundreds of thousands of residents to evacuate ahead of the landfall of a typhoon that could be one of the most destructive and expensive storms to hit the country in years.

Driving the news: Typhoon Nanmadol is forecast to make landfall on Sunday.  It's current maximum sustained winds are at 145 mph, as estimated by the Joint Typhoon Warning Center, making it a dangerous Category 4 storm. It could bring as much as 20 inches of rainfall in just 24 hours to certain areas, the BBC reports. 

Kyushu has a population of more than 13 million people. 

A “special alert” has been issued for the area, warning of potential flooding and landslides once the storm hits, the Japan Times reports.

After making landfall, the typhoon is forecast to move northeast through central Japan towards Tokyo.

Threat level: Japan's meteorological agency said Saturday that the typhoon had the potential to be more devastating than both Typhoon Jebi in 2018, which left 14 people dead, and Typhoon Hagibis in 2019, which killed dozens and caused widespread flooding and power outages, BBC reports.

Thought bubble from Axios' Andrew Freedman: "Typhoon Nanmadol is on course to slam highly populated regions in Japan, from Nagasaki to Osaka. While high winds and storm surge flooding are likely to be damaging, heavy rains and related flooding and mudslides may be the storm's greatest threat."

"Historically, typhoons that approach Japan from the southwest have tended to be extraordinarily destructive, ranking among the top 10 list of most expensive typhoons on record. It is quite possible, even likely, that Nanmadol will join this list, even though it has begun to weaken slightly as it moves toward Japan."

Typhoon Nanmadol to slam Japan, may be one of country's most expensive storms

The storm is expected to make landfall on Sunday.

Infrared image of Typhoon Nanmadol. Credit: CIRA/RAMMB

Japan

China is becoming the most formidable rival America has faced, and the risk of confrontation with Russia, North Korea or Iran still looms. Authoritarians are rising, the chaotic Afghanistan exit revealed the limits of U.S. power, and the pandemic, climate change and other critical challenges continue to pose grave threats.

World

Tropical Storm Fiona is nearing the French island of Guadeloupe, and is forecast to pass close enough to Puerto Rico this weekend to bring tropical storm conditions and up to a foot of rain. 

The big picture: The storm, which packed maximum sustained winds of 50 mph as of 5 p.m. ET, is forecast to slowly intensify, possibly to the cusp of hurricane intensity, before making landfall in the Dominican Republic on Sunday night into early Monday morning. 

Tropical storm warnings, indicating tropical storm force winds (39-73 mph) are likely somewhere within the warning area within 36 hours, are in effect for:

Antigua, Barbuda, St. Kitts, Nevis, Montserrat, and Anguilla, Saba and St. Eustatius, St. Maarten. Guadeloupe, St. Barthelemy, and St. Martin. Puerto Rico, including Vieques and Culebra. U.S. Virgin Islands and the British Virgin Islands. 

Parts of the Dominican Republic are under a tropical storm watch.  

While the storm's winds may cause damage to trees and poorly built structures, heavy rains, flooding and mudslides are T.S. Fiona's greatest threat. This is particularly the case in the mountainous terrain of Hispaniola as well as Puerto Rico. 

Data: National Hurricane Center; Map: Jared Whalen/Axios

Zoom in: Tropical Storm Fiona has been battling against a hostile environment for days, with strong upper-level winds shearing off the main region of thunderstorms away from the center of circulation. 

Yet the storm has been maintaining and lately, even improving its structure. Until Friday afternoon, the tropical storm had been moving a bit south of west, which has implications for how close it may come to the U.S. mainland. 

Conditions are expected to become more favorable for the storm to intensify as it slides just south of Puerto Rico and nears the Dominican Republic late Sunday. 

Then as it spins towards the Bahamas early next week, computer models are hinting that it is likely to intensify, possibly into a Category 1 hurricane by Wednesday. 

However, 5-day hurricane intensity forecasts are less reliable compared to storm track forecasts at that time frame. The National Weather Service is working to narrow this gap through computer modeling, in-situ storm observations and other initiatives. 

Yes, but: It's not yet clear how significant a threat this storm poses to the Bahamas, given that the right conditions in the atmosphere could allow it to intensify quickly north of Hispaniola. 

It is also not yet known how significant a threat the storm poses to the East Coast of the U.S. 

By Wednesday, there may be a pathway for the storm to curve north-northeastward, out to sea, between a cold front moving in from the west, and an area of high pressure to the east. 

The corridor in between these two weather systems may provide an offramp of sorts for this storm. 

The bottom line: It will take a couple more days for the long-term track forecast to become clearer. 

Tropical Storm warning for Puerto Rico as Fiona nears

Forecasters are watching this storm carefully.

Saturday's energy & environment stories