Hurricane Helene Unleashed Powerful Gravity Waves, NASA Video Reveals

As Hurricane Helene slammed into Florida on September 26 as a Category 4 hurricane, it brought destruction and death across the U.S. Southeast. The storm claimed over 230 lives, making it the deadliest hurricane to hit the U.S. since Katrina in 2005. In a new video, NASA has revealed huge atmospheric ripples caused by the hurricane as it made landfall, known as atmospheric gravity waves, detected by instruments aboard the International Space Station. These waves were spied by NASA's Atmospheric Waves Experiment (AWE) as they oscillated some 55 miles above the ground. The video shows the waves extending northwest of Florida, with the ripples in the atmosphere revealed by the artificially colored red, yellow, and blue bands.

"Like rings of water spreading from a drop in a pond, circular waves from Helene are seen billowing westward from Florida's northwest coast," Ludger Scherliess, AWE principal investigator at Utah State University in Logan, said in a statement. Atmospheric gravity waves occur when air is displaced vertically and then returns to its original position, creating a wave-like motion. These waves are quite similar to ocean waves, but they happen in the atmosphere instead of on water. Hurricanes can generate atmospheric gravity waves due to the intense, organized convection and rapid updrafts and downdrafts within the storm. Hurricanes have powerful convective cells within their spiral rain bands, especially around the eyewall, where warm, moist air is forced upward quickly. As this warm air rises, it creates a strong updraft, displacing air in the upper atmosphere. When this displaced air falls back toward its equilibrium level due to gravity, it sets up an oscillating motion, creating gravity waves. Gravity waves from hurricanes can be observed as ripples in cloud patterns and atmospheric pressure fields extending well beyond the hurricane's immediate area. They can also cause changes in wind patterns and turbulence, impacting other weather systems nearby. The AWE instrument, which was launched in November last year, scans the atmosphere for these gravity waves, which can also be caused by atmospheric disturbances such as violent thunderstorms, tornadoes, and tsunamis. It spots these by detecting fluctuations in the brightness of airflow in the atmosphere caused by the waves. This video marks the first images released by the AWE instrument. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about atmospheric gravitational waves? Let us know via science@newsweek.com.