A three-year old boy and his family were rescued when a fire was started outside their home in Bridlington.
In all, 17 people were led to safety when the fire spread along the roofs of a row of terraced houses in Carnaby Avenue in the early hours.
Firefighters had to break an upstairs window to reach the boy, along with a man, 22, and a 21-year-old woman. All three received hospital treatment.
The fire is thought to have been started deliberately.
Smoke alarm
Steve Topham, from Humberside Fire and Rescue Service, said the fire was started at the back of the house just before 0100 BST, then spread upwards and "raced across the roofs" of neighbouring homes.
He said: "It is a miracle that this family are alive today and that is testimony to the way that the first arriving fire crews worked.
"The key to their survival appears to centre on their smoke alarm and whilst in this case they did not escape the fire, they did have enough time to get together near to a window and await the fire engines.
"This highlights the intense dangers of fire and we appeal to families to have an escape plan and consider what their actions would be if they have a fire in their home."
A police investigation is now under way.