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 ä lgvandringen” 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 Angerman River, some 187 miles northwest of Stockholm, in the annual spring migration toward summer grazing pastures.

“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.