Two young boys are still being treated in hospital after they were hit by lightning in Brampton.

Dulce Caines, 26, and her son, Kyus, five, were at Centennial Park with another child when the storm struck on Wednesday. Kyus is in critical condition at the Hospital for Sick Children.

"He's breathing," worried father Oral Caines said outside Sick Kids.

"He hasn't opened his eyes yet."

The other little boy is just three years old. His condition was upgraded Thursday from critical to serious.

Witnesses described the blast as a fireball. They also reported that there was little warning for the lightning strike. Though the sky was dark, there was no rain and no thunder.

Several people in the area immediately rushed to the scene and began performing CPR on the two boys.

"I saw a little boy, very little," recalled Allan Hughes. He lives nearby and immediately rushed to help.

"He had bright blue eyes. He was lifeless. There was no movement in his body. There was no breathing, nothing.

"I heard a woman scream, 'Somebody call 911!' So I grabbed my phone, called it, threw my shoes on, jumped the fence, and gave a kid CPR and waited for the ambulance to get here."

The mother did not need to be resuscitated and remains in stable condition at a Brampton hospital.

The lightning bolt blasted two holes in the soccer field and scorched the fence at a nearby tennis court. Three other children and the babysitter of the younger boy were nearby but escaped unharmed.