The concerned parent called the police when her son did not return from a party in the area of Kellmünz in south-west Bavaria.
The police force searched for the missing 17-year-old using thermal imaging cameras and found him fast asleep in a builders’ excavation pit.
It was minus 10 degrees C when the drunk teenager collapsed into the ditch and fell asleep. It was so cold that he was in serious danger of freezing to death if his mum had not come to his aid, the police said.
He was taken to hospital to be treated.