Exclusive: Grieving sister speaks after 10 family members died in flash flood

And for the first time, a sister of one of the victims spoke only to us about that awful day.

"We lost half of our family, there was [sic] six grandkids, now there's [sic] only three," Luz Garnica said.

Fighting back tears, Garnica describes the day her world shattered. It was the day she lost half her family.

"This happened Saturday afternoon and they called us in the evening saying they had an accident," Garnica said.

On July 15, 2017, a massive and violent flash flood struck north of Payson without warning.

"We didn't really get the right story until the morning and then they kept on bringing bodies from eight in the morning. We were recognizing one by one," Garnica said.

The roaring wall of water rushed into a popular swimming hole where the Garnica family of 14 was picnicking. Ten of them died.

Garnica's brother, 26-year-old Hector Miguel Garnica, his wife Maria, and their three children, Daniel, Mia and Emily, were among the lives lost.

"I was able to get in contact with the detective and she told me at that moment when I found out, that they had found three bodies. One of them believed to be Maria's and the other one, one of the little girls, which was Mia," Garnica said.

It wouldn't be until days later that search crews would recover her brother's body, but they had to wait until DNA tests confirmed what Garnica says she already knew.

"But we knew by Thursday morning that it was him, because of a tattoo that he had right here, with a nickname I game him when we were very little. It was Botiz," Garnica said.

And it's the good memories, like the nickname, their childhood and high school days together, family birthdays, the day Hector Miguel became a dad and the love he had for his wife and kids that Garnica says she focuses on to help her get by.

"I don't think we have been able to process this yet so we don't know what to expect. We don't know how we're going to live without them," Garnica said.

Hector Miguel was the oldest of five. Now Garnica is. And she struggled with how to explain this tragedy to her own kids.

"I told them God needed more angels and they're looking after us," Garnica said.

Garnica tried to find the right words to explain death to her young children.

"I don't know if they understand exactly what's happening. I still don't understand, sometimes I don't realize what's going on until I talk about it. I still can't believe it," Garnica said.

As Garnica dealt with her own grief, she also had to explain the unexplainable.

"I just told them that um, Danny, 'cause they were closer to Danny, especially my 7-year-old. And I told them, 'Honey, they're not here with us anymore. God needed more angels and they took Danny and his sisters and your Tio Miguel, that's what they called him, and your Tia Maria," Garnica said.

Garnica shared old photos of her children with their cousins, only babies at the time. They were all the same age and were growing up as the best of friends. And in another photo Garnica shared, she is holding her son and her nephew Danny.

"My 7-year-old son said, 'Mom, I think I want to cry but I'm not because I don't want you to cry.' I said, 'It's OK honey. If you need to cry, just do it. We're gonna miss them.' My sister said, 'They're right here next to you 'cause they're angels. You can't see them, but they protect you,'" Garnica said.

And as the healing process continues, Garnica says, even in his death, her brother is teaching her how to live.

"I changed my point of view because now I know that, you know, you can be here one day but then tomorrow, you don't know," Garnica said.

So now she's saying... thanks.

"I just want to thank everybody, everybody, really I mean everybody. Everything they have done for the family all the support, especially all the love. I mean all of that is what keeps us, keeps us here and not breaking down," Garnica said.