To the Swiss, it is a source of huge national pride, an age-old practice in which singers take a deep breath and belt out warbling tunes across the mountains.
Now, however, yodelling is being blamed on creating the worst Covid supercluster in Switzerland and perhaps, experts say, Europe.
Scientists have pointed the finger at a yodel “musical” attended by 600 fans in late September in the rural Schwyz canton (region), in which concert-goers respected social distancing but were not required to wear masks.
"We can't do anything about what happened with this yodelling group. We found out nine days after the performances that several people from the group were infected," event organiser Beat Hegner told RTS public television.
Now the pandemic has swept through the region, with 1,238 cases compared with just 500 in mid-September. On Wednesday alone, 94 people tested positive, twice as many as the day before.
The canton has become Switzerland’s worst Covid zone, with an infecting rate of 408 per 100,000 inhabitants.
"There's an extremely high rate of positive tests," said hospital chief Franziska Foellmi.
"It's time we reacted. The explosion in the number of cases in Schwyz is one of the worst in all of Europe," chief doctor Reto Nueesch posted online.
In a video message, he said: “It’s time for you, the population, to react. Wear masks, don’t party anymore.”
Last month, an Australian study suggested that singing can spread coronavirus via airborne droplets and pose greater risks than talking. A choir singing indoors can saturate the air with infected particles.
The risk could be reduced if singers wore masks and audiences were smaller, said researchers from the University of New South Wales, Sydney.
While local Swiss authorities have stopped short of imposing a yodel ban, they have ramped up infection control measures, making mask-wearing compulsory at all public and private events with more than 50 people and in situations where distancing can't be maintained.
However, unlike other cantons with high Covid levels, it has still baulked at making masks compulsory in shops.
News of the yodel supercluster came as Swiss health minister Alain Berset warned that the situation was "deteriorating" nationwide at an alarming rate.
“For the past week... the situation in Switzerland is deteriorating faster than elsewhere,” he said.
The wealthy Alpine nation of 8.5 million people registered 2,600 new cases on Thursday - the highest daily number since the start of the pandemic. The proportion of positive tests in the country has meanwhile jumped from 5.4 to 10.2 percent in the past week.
Swiss President Simonetta Sommaruga warned that a full-blown second wave was looming.
"It is five minutes to midnight," she told reporters, urging everyone in the country to take precautions.
The country had lifted most of the measures imposed during the first large wave of infections in the spring.
But in Geneva, the hardest-hit canton, authorities this week imposed a limit for spontaneous private gatherings of 15 people, while demonstrations are limited to 100 people.
It has also imposed a mandatory 10-day quarantine on anyone arriving from a long line of countries.
While it is also practiced in Austria's Tyrol region and other mountain areas of central Europe, yodelling is seen as part of the cultural glue that binds the Swiss nation.
This week, the Swiss government even called for it to be inscribed on the United Nations global “intangible heritage” list, along with precision watchmaking and its graphic and typographic tradition that gave rise to the Helvetica font.