TORONTO - Dulce Caines saw clouds gathering Wednesday and was headed home with a group that was playing in a park when seconds later a bolt of lightning threw Caines, her five-year-old son and a three-year-old playmate to the ground, her husband said Thursday.

Little Kyus Caines was in critical condition drifting in and out of consciousness, at times trying to speak, after apparently bearing the brunt of the sudden lightning strike in the Brampton, Ont., soccer field, his father said.

"I wish it happened to me instead of him," Oral Caines said outside the Hospital for Sick Children in Toronto, where he has been by his five-year-old son's bedside.

"It's tough seeing him like that."

Kyus was listed in critical condition, while his 26-year-old mother was in Brampton Civic Hospital in fair but stable condition.

"She's doing OK," Caines said of his wife. "She's a little sore."

A spokeswoman said the three-year-old boy, who was also rushed to the Hospital for Sick Children, was improving Thursday. His condition was upgraded from critical, which means death may be imminent, to serious, which means he is acutely ill but may improve.

Kyus likes dinosaurs, playing games, riding his bike and scooter and playing cards, and hopefully he can do all that again soon, his father said.

"It's left me devastated," Oral Caines said.

Dulce Caines, Kyus, her four-year-old son and a babysitter with the three-year-old boy and another child were in a park Wednesday under what witnesses described as cloudy but not ominous skies, when the lightning strike came.

Kyus' little brother and the others were not injured.

Oral Caines said the group saw clouds moving in and had just turned to go home when out of nowhere a lightning bolt witnesses described as a "fireball" hurtled to the ground.

He believes his son was directly hit by the lightning and the other two were injured more indirectly.

People in nearby homes ran to the field and administered CPR to the two little boys, but said there were no signs of life.

Lightning can strike up to 17 kilometres away from a storm, which can make it seem the bolt has come out of nowhere, Environment Canada meteorologist Geoff Coulson said Thursday.

"There have been cases of lightning occurring 15, 16, 17 kilometres away from where the parent storm is, giving the appearance to some folks that the lightning is literally coming out of almost a blue sky," he said.

Just before the strike in Brampton rain showers were moving toward the area and the cell briefly intensified to become a weak thunderstorm with only about 15 to 20 lightning bolts, Coulson said.

That's contrasted with spectacular and sustained thunderstorms that pounded southern Ontario on Sunday night, which Coulson said generated "thousands upon thousands" of lightning flashes within an hour or two.

"One lightning bolt can be one too many depending on where it actually lands," Coulson said.

A woman was killed in Sunday's storms after trying to take shelter from lightning and rain under a rubber dingy in the Port Franks area.

Being hit by lightning is a rare occurrence, with about 100 to 150 Canadians struck each year and an average of 10 being killed by the bolt, Coulson said.

When it does occur, however, it can be a brutal experience, said the corporate chief of emergency medicine at William Osler Health Centre, the hospital network treating Dulce Caines.

"It's almost like being hit by a car because there's such a blunt force," Dr. Naveed Mohammad said of being hit by lightning either directly or indirectly.

"The force that's generated can cause injuries to your organs, break your bones, rupture your eardrums, cause hemorrhages within different parts of the body, cause hemorrhages in the eyeball."

In addition to burns on the outside of a person's body, the "immense amount of heat" created can damage vital internal organs, injuries that may not be apparent right away, Mohammad said.

What often leads to death in people who have been hit by lightning is the electricity from a jolt of lightning disrupting the heart's own electrical rhythm, Mohammad said. It may either stop the heart or send it into an abnormal rhythm that "is not compatible with life," he said.