Marathoners Waiting for Mom to Cross the Finish Line Among the Injured

April 16, 2013— -- Carol Downing's two daughters and son-in-law waited to cheer her across the finish line after they finished the Boston Marathon.

Instead, twin explosions sent shrapnel flying through the streets near the 26th mile, tearing into the bodies of Downing's daughters, Erika Brannock and Nicole Gross, and her son-in-law, Michael Gross.

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Carol Downing texted her son-in-law in the afternoon and learned he and the girls were injured. She then texted her husband, Skip Downing, who was on a layover in Kansas.

And as the Downings learned of the gravity of the injuries sustained by their two daughters and son-in-law, the day the family had trained so long and hard for turned dark.

"It's going to be a long, long road. At least everybody in our family is alive," Skip Downing told ABC News.

The family did not disclose the names of the hospitals where their loved ones were being treated. However Brannock, a 29-year-old Baltimore-area preschool teacher listed in critical condition, was expected to have the hardest road ahead of her.

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Brian Gross, Michael's brother, told ABC News that doctors had to amputate below Brannock's knee and were monitoring her other leg.

Michael Gross, of Charlotte, N.C., suffered severe upper body lacerations, Brian Gross said, and Nicole Gross, who had run the marathon with her husband, was undergoing a series of surgeries as pins hold the bones together in one of her legs.

Brian Gross' wife, Erin Gross, said the family was "hoping for the best."

"It's been heartbreaking for everyone involved," she said. "We were shocked and crushed and upset."

ABC News' Alyssa Newcomb contributed to this report.