2026 El Niño Health Risks: Six Extreme Weather Threats Facing the Americas

The Atlantic may be seeing a weaker hurricane season than in previous years, but the Americas are bracing for a different kind of threat. The National Oceanic and Atmospheric Administration, or NOAA, issued an El Niño advisory on June 11, with forecasters predicting a 63% chance of sea surface temperatures exceeding averages even more this Fall, to create a "very strong" or Super El Niño. The weather phenomenon occurs when temperatures are warmer than usual in the equatorial Pacific for several consecutive months.

While El Niño conditions will likely translate to a below-normal Atlantic hurricane season, it also acts as a chief indicator of long-lived and potentially severe thunderstorms, as well as the possibility for extreme drought in some areas. With extreme weather on the horizon, medical professionals and weather officials are warning the public about severe flooding, extreme heat, and grave health implications for vulnerable populations.

Direct Relief spoke with Dr. Ronaldo Similox, a health provider in Guatemala, who has already experienced flooding this year. Similox leads the Guatemalan-based NGO Fundación Margarita Valiente, which receives medical support from Direct Relief, and has been working to provide patient care even during extreme weather events.

Here are some of the key impacts that could create health risks this year:

Possible Increased Flooding and Coastal Erosion

Data compiled by Direct Relief's Data, Metrics, and Impact team highlights specific regions facing the highest threats from the current El Niño cycle. The heightened temperatures driven by this pattern could easily make 2026 and 2027 the warmest years on record.

Regions facing the greatest risk of flooding and coastal erosion include California, the U.S. South, and Southeastern South America. Additionally, NOAA officials reported that heavy rainstorms could originate in the Gulf of the Americas (the Gulf of Mexico) in June and July, with torrential rain expected to fall rapidly, heightening the likelihood of roadway washouts and landslides.

Potential Spikes in Respiratory and Gastrointestinal Diseases

The drastic shifts in weather could cause torrential rains and flooding, and in those areas, water supplies can quickly become compromised.

Dr. Similox of the Guatemalan-based NGO Fundación Margarita Valiente notes that this is particularly dangerous for communities that rely on traditional infrastructure. He warned that there is a high chance of gastrointestinal diseases that spread through consumption of contaminated water, noting that the Mayan people, who predominantly reside in rural areas as agricultural workers, have traditionally relied on well water.

Thriving Environments for Vector-Borne Illnesses

Stagnant water combined with warmer temperatures can create ideal conditions for the proliferation of mosquitoes, drastically increasing the risk for conditions like Zika, dengue, and chikungunya. According to Dr. Similox, these vector-borne diseases are likely to increase as river waters decrease and become stagnant, leaving vulnerable populations highly exposed as mosquitoes thrive in areas with still water and high temperatures.

Severe Malnutrition and Crop Failure in Dry Corridors

El Niño doesn't just cause flooding; it can also drive extreme drought in specific geographic zones. Parts of Guatemala are heavily affected by the Dry Corridor, a strip of land across several Central American countries vulnerable to extreme weather events.

Dr. Similox explained that the dual drought-related health threats facing this region are those of respiratory illnesses as well as malnutrition. Because the agricultural community will be subject to drier conditions, respiratory conditions could be aggravated through air pollution and dust. The arid conditions along the strip can also ruin crops and create a scarcity of food. Dr. Similox stated that malnutrition is a top concern among the most vulnerable parts of the population: children, pregnant women, and older adults.

Dangerous Inland Flooding

Many people associate tropical weather damage strictly with coastlines, but weather data shows that inland cities are often the hardest hit. The last below-normal Atlantic hurricane season occurred in 2015 (also an El Niño year), which brought record rainfall, tornadoes, hailstorms, and record-high temperatures to cities across the United States.

For 2026, NOAA officials shared caution for inland cities along the mid-Atlantic and northeastern parts of the United States. CONRED, Guatemala's risk management organization, has similarly warned its residents of June flood-like conditions affecting roadways.

Ken Graham, Director of NOAA's National Weather Service, stressed during a May 2026 press conference that more than half of storm deaths are caused by inland flooding, noting that people frequently underestimate the power of moving water. "If you live in a flood zone, be prepared for the evacuation plan. Six inches of fast-moving water will knock you off your feet. Twelve inches will carry your car away," he said.

The Critical Forgotten Danger: Medication Scarcity

One of the most overlooked health risks during a weather-related evacuation is the sudden loss of access to life-saving prescription medications. When forced to leave their homes quickly, many individuals fail to pack a sufficient supply of their daily medical necessities.

Graham warned that preparedness is key, as flood conditions are likely over the next few months, leaving many people unprepared to evacuate for a week at a time. Reflecting on recent disasters, including Hurricane Helene, which saw extreme inland flooding, Graham shared a vital reminder for anyone living in a high-risk weather zone. "The last winter storm event really opened my eyes on something. There were a lot of fatalities of people who didn't account for medicines," he said. "We have to remind people over and over that you're not going to have access to those things for a week at a time or more after a storm."

Direct Relief operates a hurricane preparedness program that prepositions caches of essential medications, including those needed to manage chronic conditions such as diabetes, high blood pressure, and asthma. These caches are placed in storm-prone communities throughout the U.S. Gulf and East Coasts, Caribbean, Central American, and parts of the Pacific.

The organization will continue to respond to health needs resulting from extreme weather events around the world.