A lost American student survived for five days alone in the Grand Canyon wilderness - until rescuers spotted the giant 'Help' she wrote with rocks.

Amber VanHecke, 24, had no map and no mobile phone signal when her car ran out of petrol on a sight-seeing road trip on 12 March.

The former girl scout told ITV's Good Morning Britain how bars of signal would appear on her phone intermittently, but there was never enough to make a call from her isolated spot near the Grand Canyon's South Rim in Arizona.

Describing the moment a van drove past but did not see her, Amber said: "That was probably the hardest moment. It was on the fourth day. I remember hearing something that sounded a little louder than the aeroplanes I'd gotten used to hearing overhead.

"By the time the truck was coming behind my car, they were going faster than the 35 mile speed limit in that area - that was the last speed sign I'd seen.

"I immediately jumped out of my car thinking I could catch them and get their attention. These were dirt routes, so there was a dust cloud behind the truck and they didn't see me or hear me. I remember just doubling over and crying intensely."

Amber told how she tried a range of techniques to get herself noticed, but to no avail.

She said: "I also tried a signal fire but since everything was so dry, it burned too clean. I also made a road barricade after the truck driver drove past me without noticing.

"I had a flashing headlamp that I turned on every night. I rationed my food and water and when they found me I still had 16-18 days left."

She finally decided to walk for 11 miles in a bid to get signal, eventually receiving just enough - 49 seconds worth - to speak to the emergency services on 17 March.

Amber had just enough time to give the operator the information needed to track her.

Amber, from Denton, Texas, told how she broke down in tears when she was eventually spotted by a ambulance rescue pilot who saw her giant 'Help' sign from the sky.

Pilot Jonah Nieves said: "She was a survivor, she did a lot of things that helped her survive. Those notes were clues and those clues led us to where she was."

Once Amber was safely in hospital, she wrote on her Facebook page: "So they put me on the care flight and hooked me up to fluids and oxygen. On the bright side, I guess I got to cross riding in a helicopter off of my bucket list."