Does Viral Video Show ‘Dolphin Stampede’ During Hilary?

Tropical Storm Hilary hit the West Coast over the weekend, causing widespread flash floods and desert temperatures in California to plummet.

Hilary had strengthened to a Category 4 hurricane early Friday morning with sustained wind speeds at 140 miles per hour. Winds weakened and Hilary was downgraded to a tropical storm when it reached California on Sunday.

One viral video also claimed to show the storm’s effects on California’s native wildlife, depicting a pod of dolphins heading away from the impact of the harsh weather.

The Claim

A post on X, formerly Twitter, by user @Swaggzeez1, on August 21, 2023, viewed more than 200,000 times since, included a video of a pod of dolphins swimming together in the same direction.

The tweet stated: “🚨 This dolphin stampede was spotted along the coast in California before #californiahurricane #earthquake #Hurricane“

The Facts

Dolphins may respond to bad weather by swimming further out to sea. As natural history writer Jon Dunn explained in a 2018 article for BBC Wildlife Magazine, coastal dolphins can sense changes in atmospheric pressure and will swim to calmer waters if poor weather makes their seas dangerous.

Nonprofit research and conservation organization The Wild Dolphin Project states that in 2004, two very strong category 2/3 Hurricanes Jeanne and Frances in the Bahamas led to a 30 percent disappearance of spotted and bottlenose communities in the region.

Cindy Elliser, research director and founder of Pacific Mammal Research, told the project: “Based on their history and residency I believe they died, if they had moved I would expect to have seen them in a neighboring community (in the Abacos, Bimini or even [Florida]), and none of those lost dolphins have been sighted again.”

Elliser added that storms can change the availability of food, as hurricanes can kick up dirt and sand in shallow water, killing fish by doing so.

It would make sense, therefore, that the effects of a tropical storm such as Hilary could have led dolphins to swim out elsewhere.

However, the video shared on social media does not depict this.

It was posted in November 2022 on World Ocean Day’s Facebook page and months later on YouTube and Instagram, captured, it states, on the Southern California coast near San Diego.

So, although the video was filmed in California, it has nothing to do with Tropical Storm Hilary.

The likelihood of such footage having been captured over the past week would have been slim in any case.

Although it has since canceled its tropical storm warning, the National Weather Service San Diego published multiple alerts as Hilary approached, stating: “Very strong winds will cause hazardous seas which could capsize or damage vessels and reduce visibility.” It also advised that mariners should “remain in port, seek safe harbor, alter course, and/or secure the vessel for severe wind and seas.”

The Ruling

False.

Although dolphins do head to deeper, calmer waters during storms and adverse weather conditions, the video shared on social media was not filmed recently.

It has been online since at least November 2022 and posted elsewhere since. Although shot in Southern California it has nothing to do with Tropical Storm Hilary.

FACT CHECK BY Newsweek’s Fact Check team