The multiple world champion announced her decision "to move forward with new leadership" at the end of the season but Day has already left the camp, it has been reported.

"After working with Mike Day for seven seasons, I’ve decided to move forward with new leadership on my team for the next phase of my career," Shiffrin said in a statement.

"I want to thank Mike and acknowledge all of his work and dedication over the last several years."

Day's immediate departure came as a "shock" for U.S. Alpine director Patrick Riml.

"Mikaela wants to do something different going forward," Riml was quoted as saying by The Associated Press.

"She wants a new challenge.

"And she informed Mike and Mike decided to go home.

"It’s a shock for me that he took off."

U.S. Ski and Snowboard announced that Shiffrin will be "supported closely by the Stifel U.S. Alpine Ski Team coaches for the remainder of the season".

Day first joined the U.S. Ski and Snowboard coaching set up in 2010, serving as the men's technical head coach until 13 before re-joining as women's technical head coach in 2016.

Shiffrin won a silver medal in super-G last week at the World Championships and is set to the giant slalom and slalom in France.

The 27-year-old broke Lindsey Vonn's record of 82 World Cup wins this season and is one win away from Swede Ingemar Stenmark's overall mark of 86 wins.

She is part of a group of around 140 athletes, Aleksander Aamodt Kilde of Norway and Federica Brignone of Italy, who signed a letter calling on the FIS to do more to tackle climate change, dismissing the governing body's sustainability efforts as "insufficient".

The Alpine Ski World Championships is set to conclude on Sunday (February 19)