An amber warning for snow has been issued by the Met Office for the Norfolk and Waveney coast, with heavy snowfall expected until at least 10am.
A yellow weather warning has been in place for Norfolk as the 'Beast from the East' cold front moves over the country.
But at midnight it will be upgraded to the second highest level for areas around the coast, which could see up to 20cm of snowfall.
The Met Office said: 'Heavy snow showers are expected overnight and during Wednesday morning.
'Travel delays on roads are very likely, with snow perhaps leading to some stranded vehicles and passengers; delays or cancellations to rail and air travel are also likely.
'Some rural communities could become cut off. Power cuts may also occur and other services, such as mobile phones, may be affected.'
Delays are currently affecting First Norwich buses, particularly on routes through Grapes Hill, Ketts Hill and Prince of Wales Road.
The company has told passengers to expect delays on all services as they are only serving main routes.
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