Several homes were flooded, but The Environment Agency said "things could have been a lot worse".
A spokesman said water had come within a few inches of overtopping significant flood defences.
More high tides were set to affect the area on Friday evening and on Saturday morning and three severe flood warnings remain in force in the county.
Places affected included Minsterworth, Maisemore, Elmore and Newnham.
Dave Throup from the Environment Agency said it had been a "very close shave".
"The levels here do rise remarkably quickly. The locals haven't seen anything like this since 1999.
"It is an unusual set of circumstances with the surge as it was.
"[The water] was within a few inches of overtopping some significant defences."
Earlier police urged sightseers to stay away from the river.
A Gloucestershire Police spokesman warned motorists the situation could change rapidly.
River Severn expert Chris Witts said although the bore wave was "fairly small", it was to be expected because of the large amount of fresh water coming down the river.
"The tide had to push against that and had to overcome the bore - it's reversed the flow and is looking quite spectacular and that flow's fast," he added.
Rest centres in Tewkesbury and the Forest of Dean have opened while those in Stroud and Gloucester remain on standby.
The Severn Bore occurs when a large tidal surge pushes sea water up the Severn Estuary and into the River Severn.
It can travel as far upstream as Gloucester.
In Bristol, part of the A4, The Portway - which runs beneath the Clifton Suspension Bridge - was partially blocked by flooding.
A number of other roads flooded in the city, including Cattle Market Road and Cumberland Road, which caused delays to morning rush hour commuters.
A flood barrier was used for the first time protecting homes in Avon Crescent.
In Weston-super-Mare and Clevedon debris has been cleared from roads after earlier high tides.
In Somerset people called the BBC to report hailstones "bigger than the size of two pence pieces" falling over much of the county.
Several homes were flooded close to Porlock Weir but the Environment Agency said the county had escaped widespread flooding because winds had not been as strong as expected.
Bristol Rovers's football match against Crawley, due to be played on Saturday at Broadfield Stadium, has been called off due to a waterlogged pitch.
The River Severn in Gloucestershire burst its banks after a combination of high tides and the Severn Bore.