Every Texan knows what color the water in Galveston is: brown, with a tinge of sickly greenish yellow. The Gulf of Mexico’s unfortunate hue, combined with not-quite-white beaches, tarballs, the occasional sargassum invasion, and a horizon dotted with offshore drilling platforms, are what give the Oleander City its peculiar charm. It may not be South Beach or Saint Tropez, but it is just 45 minutes from Houston on I-45. (Depending on the traffic, of course.)

So imagine the surprise of visitors who arrived in Galveston over Memorial Day weekend to discover crystal-clear, aquamarine water lapping against sugar-white sand. Word of the miraculous transformation quickly spread through social media, along with photographic proof.

Local news stations sent helicopters into the air to capture the blue water from above, andABC 13 Houston illustrated the change by juxtaposing file footage of how the water typically looks next to recently taken video.

https://twitter.com/abc13houston/status/1001964083158110208

Ordinary beachgoers posted unexpectedly glamorous selfies and tweeted out their shock.

Galveston has clear water? Drake has a kid? What the hell is going on — ᴊᴜɴᴇ 14ᴛʜ (@junderscorew) May 30, 2018

God cleared up the waters in Galveston so Lebron can come to Houston.

I have no words.

Wow. https://t.co/Ydc3ggetFA — Sethooo (@seth_medina) May 30, 2018

The beautiful scenery left local business people surprised–and unusually bereft of customers. Emma Reed, a bartender at the rooftop bar of the Tremont House hotel in downtown Galveston, was expecting a busy Memorial Day weekend. Instead, the bar was nearly empty. “I guess the water brought all the people down to the beach,” she said on Wednesday, when the water had returned to a more familiar shade of beige. “Every now and then we’ll get a nice blue-green, but I’ve never seen the water that blue.”

City officials attributed the unexpected cerulean waters to the “current changing from east to west,” as the scientists at the National Weather Service speculated that Subtropical Storm Alberto may have pushed a “plume” of clear water toward the Gulf Coast on its way up the east coast. (Sediment churned up from the Houston Ship Channel—not pollution, as is sometimes alleged—is largely responsible for Galveston’s typical brown water.)

Galveston beach goers treated to relatively blue water. Ocean currents coming from the southwest pushes river sediments up the coast and turbidity of the water improves. Unfortunately the brown water will return when the currents switch. pic.twitter.com/Isyz1DOz5i — NWS Houston (@NWSHouston) May 31, 2018

Galvestonians recognized the turquoise water as unusual. “Normally the water doesn’t get that way until the end of August, when the prevailing winds start switching around,” said Stephen Sollenberger, a longtime local, while sitting on a beach chair on the Seawall on Wednesday, next to the Duck Tours amphibious truck he co-operates. “They say it’s because of the storms we just had.”

Weekend visitors were just happy to time their visit for the clear waters. Friends Candace and Christy, who had traveled to Galveston on vacation from Dallas and Kentucky, respectively, were sitting on the beach under the shade of umbrellas near the Pleasure Pier on Wednesday. (They declined to give their last names.) “It was bluer yesterday, but it’s still more blue than we had been told to expect,” Candace said. “It’s definitely darker today,” Christy added.

A reality check of sorts came from Calvin Browne, who lives in Sugar Land but was born and raised in Barbados. He was enjoying a drink on the Tremont House rooftop bar, which overlooks the Galveston harbor. “I know blue,” he said when asked what he thought of the water. “Let’s just say there’s room for improvement.”