Henry Turner, who was on the ride with his wife, daughter and two nephews, said: "The ride had completed the first half and had reached the peak for the second descent.
"Instead of descending everything stopped and we were left facing upwards." Turner said they were told the ride's safety features had "kicked in because of the rain".
He said one girl was "crying hysterically" but they were eventually lowered so they could all get off apart from the man who had back pain.
An onlooker said "About four fire trucks suddenly arrived and some people had been stuck on the ride for two hours.
"We heard the man they had to bring down had been suffering from back pain."
The fire crews battled for an hour and a half with theme park staff after the rollercoaster suddenly stopped during heavy rain.
The man was rescued using a cherrypicker.
Thrill-seekers were trapped in their seats, facing up to the sky, when the Wipeout ride halted without warning.
Five fire crews, with a high-rise ladder platform from Great Yarmouth, raced to the scene after being alerted to a "rescue from height".
Firefighters and theme park staff battled to bring the ride down so they could get into a position to rescue the man.
Mobile cutting machines were also used by firefighters to cut away part of the car to enable the patient to be taken away by stretcher.
Group Commander Ali Moseley from Suffolk Fire and Rescue Service said the rescue operation took about an hour and a half from 3.50pm when they were called.
He said: "I understand the incident commander when they arrived were working with the staff who did a really good job in getting the rollercoaster down to a lower platform.
"The car was still about three metres off the ground but in a far better position in terms of trying to reach him.
Moseley said they "did well" in helping to make it much easier and quicker to reach the injured man.
"We did have to use cutting gear to make space to get the casualty into a position where he could be put in a stretcher safely."
A spokesman from the East of England Ambulance Service Trust said they were called at 3.46pm to a man who was stuck on a ride due to the back pain.
"We sent a rapid response vehicle and an ambulance crew and treated a man, believed to be in his 40s.
"He was taken to the James Paget University Hospital for further care."
The spokesman said the man's condition was not believed to be life threatening.
Ambulance crews left the scene at about 5.30pm.
A spokesman for the theme park was unavailable to comment but told the BBC it was "a minor incident that was dealt with by [our] team."
On their website there is a description of the ride which reads: "It's not called Wipeout for nothing, the current will sweep you along the region's largest rollercoaster at 50mph.
Surely nothing could be better (or worse) than twisting and turning at high speed up hills, through loops and speeding through the station at top speed?
"Well try doing it backwards! The boomerang style ride makes sure you can't rest too easy before mixing it up and sending you back the other way, of and upside down too!"
On Twitter at 5.11pm, @bryonydaviesxo said people had been "stuck on the ride" for two hours.
An investigation into the drama is set to be launched today.
Suffolk Fire and Rescue Service shared a picture of the scene as they tried to help the trapped passengers yesterday afternoon.
Posting to Facebook, a spokesman wrote: "We're working with Norfolk fire and East England Ambulance at Suffolk theme park to rescue man from carriage many thanks to Pleasurewood Hills for support."
They added: "Great team effort including Combined Fire Control for intelligent mobilising to this unusual incident."
