Police have urged motorists to take extra care as heavy snow falls across Kent.
The Met Office said up to 2in (5cm) of snow had already fallen in places across the South East.
Kent Police said blizzards were causing poor visibility for drivers in some areas and plunging temperatures overnight could make roads very icy.
Southern and Southeastern have cancelled some services on Saturday in anticipation of more snow.
The Met Office expects up to 8in (20cm) of snow to fall in the South East on Saturday.
Supt Peter Wedlake, of Kent Police, said: "Anyone travelling this weekend should be prepared for delays and hazardous conditions.
"Kent Police is working with partner agencies to keep traffic on the road network moving, but some roads will clearly be more affected by the icy conditions.
"Motorists should be prepared. Please consider your safety and decide if your journey in these conditions is really necessary. If you do travel, make sure you have provisions for emergencies.
"We are expecting a high volume of traffic to leave Kent to travel to Europe this weekend which, together with the forecast conditions, may lead to the implementation of Operation Stack."
A spokesman for Southeastern said: "Network Rail has advised that there will be freezing temperatures overnight with a heavy frost tomorrow morning, more snow is forecast for Saturday.
"Network Rail will run de-icing trains overnight and we will be running ghost trains on their behalf to try and stop ice forming on the tracks.
"Despite all these efforts there is likely to be some disruption to the service on Saturday."