Before Swedish slow TV hit “The Great Moose Migration” began airing Tuesday, Ulla Malmgren stocked up on coffee and prepared meals so she doesn’t miss a moment of the 20-day, 24-hour event.

“Sleep? Forget it. I don’t sleep,” she said.

Malmgren, 62, isn't alone. The show, called “Den stora älgvandringen” in Swedish, and sometimes translated as “The Great Elk Trek” in English, began in 2019 with nearly a million people watching. In 2024, the production hit 9 million viewers on SVT Play, the streaming platform for national broadcaster SVT.

The livestream kicked off a week ahead of schedule due to warm weather and early moose movement. Malmgren was ready.

From now until May 4, the livestream's remote cameras will capture dozens of moose as they swim across the Ångerman River, some 187 miles northwest of Stockholm, in the annual spring migration toward summer grazing pastures.

Not much happens for hours at a time, and fans say that’s the beauty of it.

“I feel relaxed, but at the same time I’m like, ‘Oh, there’s a moose. Oh, what if there’s a moose? I can’t go to the toilet!’” said William Garp Liljefors, 20, who has collected more than 150 moose plush toys since 2020.

“The Great Moose Migration" is part of a trend that began in 2009 with Norwegian public broadcaster NRK’s minute-by-minute airing of a seven-hour train trip across the southern part of the country.

The slow TV style of programming has spread, with productions in the United Kingdom, China and elsewhere. The central Dutch city of Utrecht, for example, installed a “fish doorbell” on a river lock that lets livestream viewers alert authorities to fish being held up as they migrate to spawning grounds.

Annette Hill, a professor of media and communications at Jönköping University in Sweden, said slow TV has roots in reality television but lacks the staging and therefore feels more authentic for viewers. The productions allow the audience to relax and watch the journey unfold.

“It became, in a strange way, gripping because nothing catastrophic is happening, nothing spectacular is happening," she said. "But something very beautiful is happening in that minute-by-minute moment.”

As an expert and a fan of “The Great Moose Migration,” Hill said the livestream helps her slow down her day by following the natural rhythms of spring.

“This is definitely a moment to have a calm, atmospheric setting in my own home, and I really appreciate it,” she said.

The calming effect extends to the crew, according to Johan Erhag, SVT's project manager for “The Great Moose Migration.”

“Everyone who works with it goes down in their normal stress,” he said.

The moose have walked the route for thousands of years, making it easy for the crew to know where to lay some almost 12 miles of cable and position 26 remote cameras and seven night cameras. A drone is also used.

The crew of up to 15 people works out of SVT’s control room in Umeå, producing the show at a distance to avoid interfering with the migration.

SVT won’t say how much the production costs, but Erhag said it's cheap when accounting for the 506 hours of footage aired last year.

Erhag said Swedes have always been fascinated by the roughly 300,000 moose roaming in their woods. The Scandinavian country’s largest animal is known as “King of the Forest.” A bull moose can reach 6 feet 10 inches at shoulder height and weigh 992 pounds.

Despite their size, the herbivores are typically shy and solitary.

“We actually don’t see it very often. You often see it when you’re out driving maybe once or twice in your life,” Erhag said. “I think that’s one thing why it has been so, so popular. And then you bring in the nature to everyone’s living room."

Hanna Sandberg, 36, first began watching the show in 2019, though she didn't spot any moose. She tuned in the following year, finally saw some and got hooked.

“You can watch them and be a part of their natural habitat in a way that you could never be otherwise,” she said.

After hours of showing an empty forest, a camera captures footage of a moose approaching the riverbank. Suddenly, slow TV turns urgent.

The push alert hits SVT's app — “Första älgarna i bild!” which translates to “First moose on camera!” — as viewers worldwide tune in. The livestream's chat explodes as commenters type encouragement for the animal, now making its way into the water.

”I would actually like to be a little fly on the wall in every household that watches the moose migration. Because I think there is about a million people saying about the same thing: ‘Go on! Yes, you can do it!’" Malmgren said.

Mega-fans like Malmgren, who is in a Facebook group of 76,000-plus viewers, are committed to watching as many hours as possible. Some viewers on Tuesday posted photos of their dogs and cats staring at their televisions, enthralled by the moose on the screen.

“I was late to school because I saw moose and my teacher was like, ‘What, you saw moose in the city?’ And I was like, ‘No, it’s on the TV,’” Garp Liljefors said ahead of Tuesday's showing.

Malmgren said friends and family have learned not to bother her when the moose are on the move.

“When someone asks me, ‘What are you doing? Oh, never mind, it’s the great migration,’" she said. "They know.”