It happened just before 1:00 p.m. Wednesday near East Cedar Avenue in Wildwood.
Witnesses Charlene Schriver and her sister Therasa Stephenson said the storm moved in quickly, no lightning and no thunder, just a torrential rain.
Authorities say the four family members were huddled under an umbrella during a storm.
The family included two women, one of whom was pregnant, a man and a child.
"There was a big huge flash, he bounced, we saw him bounce and then everyone just kind of freaked," Stephenson said.
Stephenson said the man was holding the umbrella. He bounced off the ground.
"I can't even get that out of my head. He was convulsing on the ground; he was talking at least. He was telling his family to get away," Stephenson said.
A woman also appeared to have taken some of the force from the bolt.
"She was also on the ground just shaking saying she just felt everything and they were trying to get the dad to calm down," Stephenson said.
The two adults were taken to Cape Regional Medical Center.
The pregnant woman and her child rushed to get out of the storm and went home. They too were later transported as a precaution.
The Wildwood Fire Department says all four are expected to survive.
"I thank God. We've been praying, we are just thanking God that everyone is ok that we didn't see anything worse," Stephenson said.