A teenage girl with a genetic disorder has said Apple's Siri software helped save her from Hurricane Harvey.

Tyler Frank, 14, was stranded on the roof of her house for two days.

The teenager who suffers from sickle cell anaemia, which prevents her red blood cells from transporting oxygen properly, was experiencing severe pain with only a wet towel to keep her warm as waters rose.

But after her calls to emergency services and pleas on social media failed to get attention, she said the voice-activated software allowed her to call the coastguard, which eventually rescued her.

Ms Frank, along with her mother and three brothers, told CNN that they awoke in the early hours of 27 August to find flood waters up to her chest.

Ms Frank's oldest brother, 18-year-old Joseph, carried her to the roof on his back. Her middle brother Brayland, 16, carried up their youngest, eight-year-old Jaquarus.

The cold conditions triggered Ms Frank to have a sickle cell crisis — which occurs when blood cells get stuck in blood vessels. It left her in extreme pain.

With no sign of imminent rescue the teenager said she thought of Siri.

She told CNN: "I was like, 'Siri's smart enough, Let me ask her'."

After using it to call the coastguard, a helicopter arrived the following afternoon. But rescuers told the family they could only take the elderly, since there was an overwhelming number of people in need.

"I told him yes, I have a child with sickle cell, and she's very sick, and I need you all to take her," said Tyler's mother, Tameko Frank. “She was standing right there in front of him. And he turned around and got on the helicopter and left.”

The Hurricane Harvey Response Joint Information Center said that rescue crews "made determinations based on emergent factors" like immediate life threatening situations and "the conditions faced on the scene."

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After calling the coastguard again with the number Siri gave her, another helicopter arrived the next morning and Ms Frank flown to get treatment.

Ms Frank was seen by doctors three different hospitals before and was finally discharged late last week.

But the Frank family are unable to go back to their house and are now living in one room at a hotel.