It begins with a disaster, a huge one witnessed not from a distance, not via the safety of a TV news report, but up close and personal.

The horror of the Indian Ocean tsunami of 2004 is made intimate, so awful that you recoil from the screen, ducking as tree limbs and shards of debris are hurled at you and the onscreen victims in “The Impossible.”

While you don’t drown.

Then, stripped, battered, injured and doomed to infection, you try to save yourself and then others. You look for help. You find yourself depending on the kindness of strangers, people who don’t speak your language who are suffering and lost, too, for your very survival. And having children in your care, you try to cling to your humanity as you all cling — barely — to life.

“The Impossible” is a vivid recreation of a disaster made moving by a stellar cast, a gripping, “How will this end?” script and all-too-real special effects and sets.

You’ll feel you’re in that oceanic washing machine with Naomi Watts, grieve for her chances of survival and cry over the life lessons she struggles to pass on to her son (Tom Holland).

A Christmas vacation in Khao Lak, Thailand, turns terribly wrong for a family of five, headed by Maria (Watts) and Henry (Ewan McGregor).

Miraculously, they survive the tidal wave. But they’re separated — dad with two small boys of 5 and 7 years, mom with 12-year-old Lucas. We follow their stories, separately, each looking for and despairing of finding the other.

For Maria, that takes on extra urgency. She’s badly hurt, and the struggle to get Lucas and a small boy they rescue along the way to safety becomes the thing that drives her.

Lucas, a frightened, confused and rebellious kid, has staggering responsibilities thrust on him. He might be all alone in the world.

Meanwhile, Henry frantically searches for Maria and Lucas and struggles to keep his boys with him.

The genius of Spanish director Juan Antonio Bayona’s approach is the myopia here. Bayona (“The Orphange”) lets us see only what the victims see. The chaos of the aftermath, First-World survivors hurled into the Third-World abyss with everybody else is stark and alarming.

And Watts, in the best performance in an already illustrious career, makes us feel it all. The effects make “The Impossible,” based on the true story of a Spanish family caught in the tsunami, wholly credible and real. But Watts and young Holland make us feel it, and make this the most moving and the best film of 2012.