The woman, who wanted to remain anonymous, said the youngster had wet the bed every night since wind damaged the Kirkham YMCA Rural Splash building on Saturday.
She said: “She is scared of the wind. I took her to see Santa’s grotto and she wouldn’t get out of the car.”
She added: “They were around 10 children [in the pool at the time] and they could have died.
“It sounded like a plan had landed on the roof and it started lifted.
“They [staff] said they would be in contact with parents but no-one has been.
“The swimming teachers were great. They handled it really well.”
Swimmers were evacuated from the community leisure centre, in Station Road, after a section of the roof blew off, with three fire engines, a cherry picker-type aerial ladder platform, an urban search and rescue team, and a command unit, called out to help.
Firefighters removed loose debris from the exterior of the roof and worked with the council to make it as safe as possible.
YMCA Kirkham Rural Splash used social media to say the building would be “closed until further notice”.
“Unfortunately the storm today has done some severe structural damage to part of YMCA Kirkham Rural Splash,” it said.
“We will update you soon. We apologise for any inconvenience but safety is our priority.
“Thank you for your continued support as always.”
Patrons commented on the post to praise staff and their quick reactions.
One person said: “Staff were brilliant making sure the children and parents were ok and that nobody was hurt.
“They stayed very calm in an extreme situation which I’m very thankful for.”
Another added: “Thanks to everyone at YMCA for managing it so well - pretty scary stuff for adults as well as the kids.
“So thankful nobody was hurt.”
YCMA said it would contact members soon to “provide more updates when they become available”.
“The recent bad weather and high winds has caused severe damage to the infrastructure of YMCA Kirkham,” a spokesman said.
“A section of the roof over the swimming pool was breached and our quick-thinking staff team evacuated everyone from the centre.
“YMCA contractors and maintenance teams were on site quickly to assess the damage to the centre and as such the centre will remain closed until the area can be made safe.
“We will be in touch with members and swimming lesson parents soon and will provide more updates when they become available."