Heavy rainfall has been lashing the Westcountry - with flooding forcing the closure of many roads and rising water pouring into homes and businesses.
The torrential downpour began to sweep east over Devon later in the evening and is expected to remain persistent overnight and into much of Friday across the county.
Fears of a major flooding incident have been growing after the heavy rain swept in from the west, battering Plymouth and South Devon and moving up the county.
It follows reports of widespread flooding over the border in Cornwall earlier in the night.
Reports of floods became so widespread across Cornwall that the local authority opened its dedicated control centre to respond to the calls with authorities dealing with more than 50 reported incidents by late evening.
A Cornwall Council spokesman said: "The council has opened Silver Control to co-ordinate the multi-agency response to flooding."
Rising water has started to flood many properties with homes and businesses in Newlyn among the worst-hit places battling to keep the floods at bay.
The council spokesman said there had been reports of flooding across the west of the county, including around Penzance and Mevagissey in Mid Cornwall – a community still recovering from the impact of last year's torrential downpours.
The council said there had been reports of flooding on the A30 at Scorrier, Chiverton and the Avers roundabout, on the road between St Ives and Trink Hill, at Tregony and the Britannia Inn at Par, Gweek to Constantine, deep ponding on the road between St Day and Lanner, and the road between Camborne and Praze, among other areas.
Police have been warning motorists in some of the worst-hit areas against driving, as officers deal with a surge in call-outs.
Sgt Dave Opara, based in Plymouth, said: "I would advise motorists not to make journeys that aren't absolutely necessary. There has been a considerable amount of rainfall across the force area. There will be more to come throughout the night, so the situation is not going to get much better too soon."
He said the force had received "a significant increase" in weather-related calls, prompting fears of further floods overnight.
Charlie Powell, a spokesman for the Exeter-based Met Office, had earlier warned of a "seriously large amount of rain" in parts.
Persistent rain is also expected throughout the day on Friday in Devon and Cornwall.
Up to 60mm of rain (2.4 inches) was predicted in many parts over 30 hours until the end of the day, equal to more than half of the average monthly rainfall in March.