A fairground worker screamed as a bouncy castle blew away, killing a 7-year-old girl inside, a court heard.
Summer Grant, from Norwich, died after the incident at the fair in Harlow, Essex, on 26 March 2016.
Shelby Thurston, 29, told Chelmsford Crown Court she tried to grab hold of the bouncy castle after "a gust of wind" blew it away.
She and her husband, William Thurston, 29, deny a health and safety offence and manslaughter by gross negligence.
Breaking down in tears as she gave evidence in the dock, Mrs Thurston said her husband ran after the inflatable circus dome and carried Summer out, putting her in the recovery position.
"She wasn't speaking. She was responsive, her eyes were blinking. It was just horrible to see," she said.
Mrs Thurston took Summer's grandmother and her sister Lilly to a caravan to keep them warm.
"Lilly said something that broke my heart," Mrs Thurston said as she wiped away tears with a tissue, "She said, 'I think Summer's poorly'".
The court heard Summer only had "a few minutes" left of her turn on the bouncy castle, but Mrs Thurston said she decided to "let them finish their go" before taking the inflatable down.
Asked why she decided to let them finish, she said: "At the time there was no concern... we hadn't reached or got very close to our critical point for wind."
Mrs Thurston said the bouncy castle had been anchored to the ground with 17 stakes and that she and her husband had been assessing weather conditions and checking if inflatables were showing "signs of the wind".
Prosecutors said Mrs Thurston and her husband, of Whitecross Road, Wilburton, Cambridgeshire, failed to "adequately anchor" the bouncy castle.
Mrs Thurston said her father had bought the bouncy castle in 2014 and that operating instructions had been destroyed in an arson attack the following year.
Summer, who died of "multiple traumatic injuries to the head, neck and chest", had been visiting the event at Harlow Town Park with her father Lee and other relatives.
Witness Kyle Ramm had been working at Pets' Corner city farm, on the edge of the park, when he saw the bouncy castle tumble down the hill.
It hit a fence and a tree "with some force as it had snapped a branch," he said in a statement.
The court heard that the bouncy castle had been loaded into a trailer before police arrived.
The trial continues.