Sophia Bush and Daniel Fredinburg
Sophia Bush and Daniel Fredinburg at an LA awards ceremony in 2013. The pair dated for a little under a year. The star said she was 'devastated' about his death in a Mount Everest avalanche.Getty

Actress Sophia Bush has described her grief after her ex-boyfriend Google executive Daniel Fredinburg was killed in an avalanche on Everest triggered by a massive earthquake.

Writing on her Twitter account, the 32-year-old One Tree Hill star said, "There are no adequate words. Today I find myself attempting to pick up the pieces of my heart that have broken into such tiny shards, I'll likely never find them all. "

"Today I, and so many of my loved ones, lost an incredible friend. Dan Fredinburg was one-of-a-kind. Fearless. Funny. A dancing robot who liked to ride dinosaurs and chase the sun and envision a better future for the world.

"He was one of the great loves of my life. He was one of my truest friends. He was an incredible brother, a brilliant engineer, and a damn good man," she continued. "I'm devastated and simultaneously so deeply grateful to have known and loved him, and to have counted him as one of my tribe."

Fredinburg, 33, head of privacy for Google X, died of a head injury sustained during an avalanche on Everest, his sister confirmed on Twitter.

Bush and Fredinburg dated for nearly a year, and ended their relationship amicably in February 2014, a source told People magazine.

So far, 17 people are believed to have lost their lives on Everest as a result of the earthquake, in what is believed to be the worst ever disaster on the mountain.

Fredinburg, who described himself as "an adventurer, not a climber" was the head of privacy at Google X, the top secret lab responsible for a range of innovative projects, including driverless cars and Project Loon, which used balloons to provide comprehensive global internet coverage.

He recently innovated several Google projects on Everest, including plans to take a Google Street View camera to the mountain's summit.

More than 2,000 people have been confirmed dead after the 7.8 magnitude earthquake struck.