Firefighters were called to help a driver who was trapped in his car in Chelmsford.
Crews from Essex Fire and Rescue arrived at Buttsbury Wash to find his car trapped in 3ft of freezing cold water.
The man was freezing cold and was suffering from shock and possibly hypothermia.
Firefighters waded into the flood waters and rescued the man using an inflatable sledge.
Station Manager Martyn Hare said: "When we arrived, the motorist was still in his car and water had started to fill the footwells."
"It is extremely dangerous for anyone to attempt to drive into flood water without knowing how deep the water is, especially on a morning where temperatures had plummeted to -4."
Every year the fire service rescues dozens of motorists who find themselves trapped after driving into flood water.
The fire service is warning motorists not to drive through flood waters which will reach more than half of their car wheels.
Staff received almost 4,400 calls - an increase of more than 20% from the same time last year.
Hundreds of schools across the Anglia region have been affected by heavy snowfall at the weekend, forcing some continued closures.
Snow has brought major problems to roads, rail and airports across the East.