A wave the height of a four-story building was recorded off the coast of Vancouver Island, and scientists say it’s “the most extreme rogue wave ever recorded.” The 58-foot-tall giant, which appeared off the coast of Ucluelet, British Columbia, on November 17, 2020, is described in the journal Scientific Reports.
"Only a few rogue waves in high sea states have been observed directly, and nothing of this magnitude,” lead author Johannes Gemmrich, an oceanographer at the University of Victoria in British Columbia, says in the statement. “The probability of such an event occurring is once in 1,300 years."
Rogue waves are massive walls of water more than double the height of other waves occurring around them. They appear in the open ocean often without warning or apparent cause. "They look like a large four-story lump sticking out of the water with a large peak and big troughs before it," Scott Beatty, CEO of the company MarineLabs which measured the wave, tells CNN’s Caitlin Kaiser and Tom Sater. These unpredictable swells are distinct from tsunamis, which are caused by the sudden displacement of water linked to another event, like an earthquake.
The first rogue wave ever detected appeared off the coast of Norway in 1995 and measured 84 feet (25.6 meters) high, making it taller than the wave recorded in Ucluelet, according to George Dvorsky for Gizmodo. The Ucluelet wave was a record-breaker because it towered three times as tall as the surrounding waves, while the wave near Norway was just over twice as tall.
For centuries, rogue waves were part of marine folklore, and have only been accepted as legitimate by scientists in the past few decades. Due to their size and force, they can be a serious threat to ships and coastal communities. "They are unexpected, so the vessel operator has little warning. If it is high enough that it can cause some damage to the vessel, the operator has no time to change course or react to it." Gemmrich tells CNN.
In 1997, a rogue wave toppled a cargo ship, dumping some five million Legos into the sea, which have been washing ashore since. The wave off the coast of Vancouver Island was far enough from shore that no damages have been reported.
Because the waves are rare, researchers still don’t know why or how rogue waves form but suspect they arise when ocean swells, winds and currents collide and reinforce each other to produce massive walls of water.
As tools for monitoring rogue waves improve, scientists are optimistic they’ll learn more about the mysterious phenomenon. The Ucluelet wave was picked up by one of the 26 sensor buoys placed by MarineLabs Data Systems along coastlines and oceans around North America. The company has said it plans to more than double its number of sensor locations by this year’s end.
The intensity and frequency of rogue waves could be exacerbated by climate change, Harry Baker reports for Live Science. A study published in June 2020 estimates that extreme wave conditions have already increased by between 5 and 15 percent due to stronger gusts and currents from warming waters.