Thursday's National Hunt meeting at Exeter must survive an 8am inspection, with plenty of rain forecast.
The ground is already testing with 20-40 millimetres of rain forecast over the next 24 hours.
Clerk of the course Barry Johnson said: "The forecast isn't good for the next 24 hours, basically it isn't going to stop raining.
"My guess is we'll get about 20 millimetres but the met office is saying anything between 20 and 40.
"We are perfectly raceable at present, it would be heavy, soft in places, but by tomorrow we'll be heavy."