In December 2024, a powerful storm in the North Pacific generated ocean waves reaching an average height of nearly 66 feet, the highest ever recorded from space. New satellite data allowed scientists to track the energy from these waves as they traveled 15,000 miles across the globe, revealing new information about how storms impact distant coastlines.
A recent study, using a combination of advanced and historical satellite data, has challenged long-held assumptions about how wave energy is distributed. The findings, sourced from a European Space Agency report, are expected to improve models for predicting coastal erosion and storm damage.
Key Takeaways
- A storm in December 2024 produced the highest average wave height ever measured by satellite, nearly 66 feet (20 meters).
- Swells from the storm traveled for over 15 days, covering approximately 15,000 miles from the Pacific to the Atlantic.
- New research shows that a storm's dominant peak waves, not the longest swells, carry the most energy, overturning previous scientific models.
- The study utilized data from a new French-US satellite, SWOT, combined with over 30 years of observations from other missions.
A Storm's Global Journey
On December 21, 2024, a weather event known as Storm Eddie churned over the open waters of the North Pacific. During its most intense phase, the storm generated waves with an average height of almost 66 feet. This measurement, captured by orbiting satellites, represents a new record for the highest average wave height observed from space in over a decade.
While the storm itself remained far from land, its impact was felt across the world. The storm created powerful ocean swells—long, smooth waves that separate from their source and travel vast distances. These swells are essentially messengers, carrying the storm's energy across entire ocean basins.
Researchers tracked the swells from Storm Eddie for more than 15 days. The waves journeyed an estimated 15,000 miles, starting in the North Pacific, passing through the Drake Passage near Antarctica, and eventually reaching the tropical Atlantic Ocean by January 6, 2025. This extensive travel highlights how events in one part of the world can have far-reaching consequences thousands of miles away.
Understanding Ocean Swells
Unlike the choppy, wind-driven waves seen near a coast, ocean swells are organized patterns of energy that can travel for weeks with minimal loss of power. Their key characteristic is the 'wave period'—the time it takes for two consecutive wave crests to pass a single point. A longer period, such as 20 seconds, indicates a powerful wave that has traveled a long distance from a major storm.
New Insights from Advanced Satellites
A team of scientists used data from a fleet of Earth-observing satellites to analyze Storm Eddie and its aftermath. The effort was led by the new Surface Water and Ocean Topography (SWOT) satellite, a joint mission between French and US space agencies. SWOT's advanced capabilities were combined with over 30 years of data from missions like Sentinel-3, Sentinel-6, Jason-3, and CryoSat.
This comprehensive dataset allowed the team to do more than just measure wave height. For the first time, they could analyze how the wave energy was distributed as it spread across the ocean. The results provided a significant surprise and corrected a long-standing scientific assumption.
"At the coast, seabed conditions also shape waves, for example, and these very large storms are rare – occurring roughly once a decade – which makes it hard to prove trends," said Fabrice Ardhuin, who led the study at the Laboratory of Physical and Spatial Oceanography in France.
Previously, it was widely believed that the longest waves, known as long-period swells, carried the majority of a storm's energy as they propagated. However, the new measurements from Storm Eddie told a different story. The data showed that most of the energy is actually concentrated in the storm's dominant peak waves, which have a more moderate length.
Record Wave Heights
While Storm Eddie set a record for average wave height measured from space, the highest individual wave recorded in the past 34 years belongs to Atlantic Storm Hercules. In January 2014, its waves reached 75 feet, causing damage to coastlines from Morocco to Ireland.
Improving Forecasts and Coastal Defenses
This fundamental shift in understanding wave energy has practical implications. Accurate models are essential for predicting coastal erosion, ensuring the safety of marine structures like oil rigs and offshore wind farms, and issuing effective warnings for coastal communities during major storm events.
The Role of Specific Satellite Missions
The study's success relied on the unique capabilities of several key satellites:
- SWOT: This mission uses a combination of traditional radar and wide-swath imaging. This allows it to detect very small swells, as low as 1.2 inches, and extremely long waves that older satellites might miss.
- Copernicus Sentinel-6: Although its primary mission is to monitor sea-level rise with high precision, it also provides real-time data on significant wave height and wind speed. This information is critical for day-to-day ocean forecasting used in shipping, fishing, and coastal safety operations.
By validating their models against the extreme conditions of Storm Eddie, scientists can now create more reliable tools for predicting ocean behavior. These improved models will help engineers design more resilient coastal defenses and infrastructure.
Connecting Waves to a Changing Climate
With a satellite record now spanning more than three decades, researchers are beginning to investigate potential links between the intensity of ocean storms and climate change. Ardhuin noted that while climate change may be a contributing factor, it is not the only one. The rarity of storms like Eddie makes it statistically challenging to establish definitive trends.
However, the ability to accurately track wave energy across the globe provides a new metric for monitoring storm intensity over time. As the climate continues to shift, this long-term data will become increasingly valuable for understanding how storm patterns are evolving and what that means for global coastlines.
The study of Storm Eddie demonstrates that a storm does not need to make landfall to have a significant impact. Its energy, carried by waves across thousands of miles, can still pose a threat to distant shores. By combining decades of data with cutting-edge technology, scientists are gaining a clearer picture of these powerful natural phenomena, paving the way for a safer and more predictable future.