Tracking waves is a fairly new thing and now a new piece of technology has allowed NASA and Virginia Tech to track them from space, which is an even bigger accomplishment. This is thanks to the Surface Water and Ocean Topography (SWOT) satellite, which allowed scientists to actually measure the height, speed, and length of these enormous water surges between 2023 and 2024.
The waves that they were measuring were not the ones that we see when we are on the beach every summer, they were fast-moving walls of floodwater sweeping through rivers, which had the potential to cause a lot of damage. These kinds of waves happen when there is a sudden rush of water caused by things like snow melting, big storms, or the collapse of a natural dam and they can carry large volumes of water downstream with very serious force. For reference, the Yellowstone River in Montana, the Colorado River in Texas, and the Ocmulgee River in Georgia were all hit by these dramatic surges.
The new wave tracking satellite and its impact on riverside communities
Launched in 2022, the SWOT satellite uses a high-resolution radar system called interferometric radar to scan the surface of water bodies. This new technology gives scientists a new way to monitor how rivers behave over time and how floodwaters move, which could lead to better flood prediction and possibly even early warnings in the future if there is a particularly big wave moving through the water and is about to crash into an established place. For now, they have been able to use it to track three waves and use the data to try to predict the behavior of future floods.
The first wave that scientists were able to track happened on April 2023 on the Yellowstone River. Satellite images spotted a surge almost 3 meters tall and stretching out for 11 kilometers. The reason for this giant wave of water was traced back to an ice dam that had suddenly broken apart, unleashing a powerful flow downstream toward the Missouri River.
The second one happened on January 2024, in Texas, when, after some intense rainfall, a massive wave formed on the Colorado River just south of Austin. This one was even bigger, measuring over 9 meters tall and moving at about a meter per second. It traveled an impressive 267 kilometers before reaching Matagorda Bay and was the biggest wave of its kind seen in the area that year.
The third wave was tracked in March 2024 when it hit the Ocmulgee River in Georgia, near Macon. This wave was triggered by another major rain event and was over 6 meters high. It took a slower route downstream, moving at 0.33 meters per second but still covering more than 200 kilometers.
These waves are more common than we think, and they are moving across different rivers and regions constantly, although it is only the big ones that really cause trouble.
Cedric David, a hydrologist at NASA’s Jet Propulsion Laboratory in Southern California and co-author of a new study published in Geophysical Research Letters, believes that these types of findings are extremely important for understanding the dynamics of waves in these types of rivers: “Ocean waves are well known from surfing and sailing, but rivers are the arteries of the planet. We want to understand their dynamics.”
And there is another side to this. Hana Thurman from Virginia Tech pointed out that these kinds of insights could help answer big questions about how likely flooding is and whether critical infrastructure might be in danger, which could allow for a lot of preventative measures to be implemented in areas that are prone to flooding.