Hundreds of families in Thetford, Brandon and Hockwold have been advised to leave their homes tonight and find shelter with the threat of flooding "imminent".
A warning from the government's flood information service is now in force in the area, with water levels rising on the River Little Ouse.
As of 7.22pm, flooding was expected to affect Primrose Close, The Meadows, Castle Lane, Mill Lane, Old Bury Road, Bridge Street, Riverside Walk, Canon's Close, Coney Close and Coventry Way in Thetford.
Teal Walk, High Street and Riverside Way in Brandon are also expected to be affected, as are homes in Church Lane, Hockwold.
People are being asked to move family, pets and cars to safety and follow advice from emergency service staff.
Anyone who is in immediate danger is asked to call 999.
There are eight further flood warnings and another 15 flood alerts in force across Norfolk, as of 9pm on Saturday.
At the moment, people who live in the above streets in Thetford, Brandon and Hockwold are the only ones being asked to leave their homes.
Dan Holley, of Norwich-based Weatherquest, said at 10.40pm that river levels at Abbey Heath in Thetford had reached the highest ever recorded at that site, matching the previous record set in August 1987.
He added that the River Thet had also exceeded its previous highest level at Bridgham by 15cm, a record also set in the summer of 1987.
Have you been affected by the flooding in Thetford, Brandon or Hockwold? Email: daniel.moxon@archant.co.uk
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