Park City, Utah - The US film industry's first major gathering since wildfires devastated Los Angeles began Thursday at Sundance, where Olivia Colman and John Lithgow kicked off the indie movie festival under somber circumstances.

Hollywood's annual pilgrimage to the Rocky Mountains to debut the coming year's top indie films started barely two weeks after blazes killed more than two dozen people and brought the US entertainment capital to a halt.

Festival chiefs spoke at length with filmmakers "who lost homes or were displaced" by the fires before deciding to press ahead, Sundance director Eugene Hernandez told AFP.

Among those were the team behind Didn't Die, an indie zombie movie about survivors podcasting to an ever-dwindling human population, which was partly shot in the filmmakers's now-destroyed Altadena homes.

Miley Cyrus Miley Cyrus' brother reveals family's growing concerns for dad Billy Ray in open letter

"We turned the film in, and a few days later... our homes were lost," director Meera Menon told AFP.

The film's producer and editor, who lived near to Menon, and her co-writer husband also fled their house before it was razed by the fires.

"The four of us really lost everything... our home was our dream home," added a tearful-sounding Menon, who was nonetheless driving up to Utah on Thursday to attend her film's premiere next week.

Also among the 88 features being screened in snowy Park City is Rebuilding, starring Josh O'Connor as a rancher who loses everything in a wildfire.

"It takes on an added poignance," said Hernandez.

"It's an incredible film, and one that we felt was important to show, based on that spirit of resilience," said Sundance programming director Kim Yutani.

The big opening night film this year was Jimpa, in which Colman plays a mother taking her non-binary teen to visit their gay and highly outspoken activist grandfather – played by Lithgow.

The movie premiered as new President Donald Trump said he has made it "official policy of the United States, that there are only two genders, male and female."

Lithgow said it was "extremely important" to begin Sundance with a film fostering acceptance "at this particular historical moment... when hatred is in the air."

Kylie Jenner Kylie Jenner slammed for hefty number of private jet flights during LA wildfires

Among other festival highlights, Jennifer Lopez brings her first film to Sundance this weekend with glitzy musical Kiss of the Spider Woman.

From Dreamgirls director Bill Condon, the film is based on the Broadway adaptation of Argentine author Manuel Puig's novel.

Lopez plays a silver-screen diva whose life and roles are discussed by two mismatched prisoners as they form an unlikely bond in their grim cell.

Benedict Cumberbatch stars in another literary adaptation, The Thing With Feathers, based on Max Porter's experimental and poetic novel about a grieving husband and two young sons.

Rapper A$AP Rocky and late-night host Conan O'Brien make up the eclectic cast of mystery If I Had Legs I'd Kick You.

And The Bear star Ayo Edebiri teams up with John Malkovich for thriller Opus, about a young writer investigating the mysterious disappearance of a legendary pop star.

Among Sundance's documentary selection, which has launched several of the most recent Oscar-winning nonfiction films, politics will feature heavily.

Former New Zealand leader Jacinda Ardern is expected in town to promote the behind-the-scenes documentary Prime Minister.

Two films touching on the Gaza assault will see their debut, days after the ceasefire agreement with Israel began.

Coexistence, My Ass! follows Jewish peace activist-turned-comedian Noam Shuster-Eliassi, as she constructs a one-woman show and grapples with the consequences of Israel's brutal siege.

"As an activist, I reached 20 people, and in a viral video mocking dictators, I reached 20 million people," she told AFP, admitting she is "anxious" about how the film will be received.

Palestinian-American director Cherien Dabis will unveil All That's Left of You in a prominent Saturday evening premiere at Sundance's biggest venue.

Sundance runs until February 2.