1 Dead After Sisters Are Swept Away by Flash Flood - But Could Tragedy Have Been Prevented?

Crystal Abrahim has been left wondering why their tour guide allowed them to cross the raging river at the time.

The sister of a California woman killed after being swept away in a flash flood in Hawaii in December is opening up about their desperate final minutes together, and that the tragedy could have been avoided.

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Crystal Abrahim spoke to Inside Edition about how she saw her 32-year-old sister, Aimee, get swept away during a dream vacation in Kauai, Hawaii.

"I can't describe it in any other way than just a nightmare," Crystal said.

Aimee and Crystal were kayaking and hiking along the lush Wailua River, when they came to a point in the tour where they had to cross the river on foot.

Suddenly, disaster struck as the sisters were picked up by the rushing waters. Aimee was killed. Now some are asking could this tragedy have been avoided.

“I kept thinking, ‘I have to find Aimee, I have to find Aimee.’ I knew I was alive,” she said.

Video taken by other adventurers show tourists crossing the same river while clinging to a rope. One person can be seen struggling and losing her balance.

Inside Edition followed the same path taken by the sisters on their fateful vacation.

Signs clearly warn of the dangers of flash floods.

Crystal wonders why their tour guide let her and her sister cross when, at the time, a flash flood warning was reportedly in effect.

"The water just started gushing super quickly I turned to Aimee and Aimee was literally stretched out, she couldn’t even hold on any longer," Crystal recalled.

Crystal and her sister were washed downstream. Aimee drowned. Crystal was slammed into rocks but survived. Her injuries are still visible on her body.

Those final minutes of Aimee's life will forever torment Crystal.

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"Trying to accept that she's not going to be in my life anymore has been the hardest thing that I don't wish anyone,” Crystal said. “I turned to Aimee for every little thing. Knowing that she won't be there anymore is the hardest thing.”

"[We] regularly monitor weather conditions," tour company Kayak Wailua said in a statement. "Water conditions were not above the cautionary threshold when the tour left... Conditions changed in minutes."

A GoFundMe page has been established in Aimee's memory.

The victim's family is considering legal action against the company. State officials say the company is compliant and in good standing -- though this incident remains under investigation.

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