Thursday's meeting at Fontwell is in serious doubt with several areas of the track waterlogged and more rain forecast.
Officials at the West Sussex track have called an 8am inspection on Wednesday and fear the worst.
"We have still got three or four areas that are waterlogged. We have seen some improvement in other areas of the course, but those areas have got worse if anything and it's been dry since Monday lunchtime," said clerk of the course Edward Arkell.
"If we are not going to be fit to race tomorrow there is more rain forecast from Wednesday afternoon onwards, so it is better we let everybody know and they can make alternative running plans. It's going to be a struggle."
Meanwhile officials at Musselburgh have called a precautionary inspection for 8am on Wednesday ahead of the meeting that afternoon. Ground conditions are described as good, but with a "tricky forecast".
Clerk of the course Harriet Graham tweeted: "Precautionary Inspection 8am due to forecast snow starting between 7-9am changing to sleet/rain later +3 Tricky forecast."
An 8am precautionary inspection has also been called for Wednesday's meeting at Thurles due to the uncertainty of the weather forecast.
A provisional all-chase card has been programmed by the British Horseracing Authority for Sandown on Friday in an attempt to safeguard the fixture. This will consist of the three chases originally scheduled plus three additional chase opportunities.
All additional races will be free to enter and a final decision on whether the existing hurdle races will be abandoned and the provisional chases activated will be made at 8am on Thursday.
Clerk of the course Andrew Cooper said: "Parts of the hurdle course are saturated. We are expecting further rain on Thursday, with some forecasts suggesting as much as 10mm. To give ourselves the best chance of staging a day's racing we have asked BHA to provisionally schedule an all-chase card ."
5 February 2016Hunting star On The Fringe returns at Leopardstown
Can Bellshill give Yanworth something to think about at Leopardstown?
Outlander and Pont Alexandre loom large in Flogas Chase
Triumph Hurdle favourite Ivanovich Gorbatov bids to cement Festival place
Alan King outlines plans for star juveniles
Rebecca Curtis runners dominate West Wales National field
Tea For Two targeting Grade One double in Scilly Isles date
Sir Des Champs goes for more Gold for Gigginstown
Noel Meade surprised by Road To Riches' odds in Gold Cup test
Nina Carberry misses On The Fringe mount following back injury
Peace And Co out to prove he is a genuine Champion Hurdle contender
Victoria Pendleton heads to Wadebridge to continue riding experience
Cold As Ice aiming to sparkle for William Haggas in Cleves outing at Lingfield
American ace Frosted puts down World Cup marker at Meydan
Alan King 'keeps it simple' and focuses solely on Neptune with Yanworth
Henry Daly sets sights on Sandown with Towcester winner Flashjack
Arkwrisht proves best for Willie Mullins at Clonmel
Harry Whittington set to swerve Cheltenham with Arzal
Ivanovich Gorbatov tops Triumph list at Cheltenham Festival
Willie Mullins makes monster Supreme entry at Cheltenham
Howard Johnson - I wouldn't have confidence for a training return
Sandy Thomson rules Seeyouatmidnight out of Wetherby heat
4 February 2016Arkwrisht proves best for Willie Mullins at Clonmel
Lifetime bans to be imposed in Ireland for drug missue
Barters Hill handed Albert Bartlett ticket at Cheltenham Festival
Alan King takes aim at Neptune with classy Yanworth
'Bouncing' Road To Riches thrills Noel Meade before Leopardstown date
Anthony Honeyball considers Lily Waugh Cheltenham Festival target
Michael Scudamore has Next Sensation on track for Cheltenham
Paul Nicholls has weighty Grand National issue with Silviniaco Conti
Welcome winner for Jonjo O'Neill at Ludlow
Saeed bin Suroor pays tribute to 'one of the best' on death of Halling, aged 25
French dark horse Maquisard could enter Triumph Hurdle picture
Allysson Monterg sets Richard Hobson a Festival poser with Leicester win
Zawraq future 'in the balance' following slow recovery process
Jeremy Kyle ITV racing role 'discussed'
Michael Scudamore admits defeat in race to get Monbeg Dude to Aintree
Television ace Brian Gleeson seeking Clonmel riches with Dont Tell No One
Mags Mullins retains faith in World Hurdle contender Martello Tower
3 February 2016Hefty Ludlow ban for amateur rider Theo Gillard
Many Clouds on course to emulate Red Rum at Aintree
Argocat nearing debut run for Nicky Henderson
Taunton hails Mary as Nicky Henderson strengthens Cheltenham hand
Gordon Elliott keeps No More Heroes fresh for Cheltenham Festival
Noel Meade forced to draw stumps with Cheltenham fancy Ned Buntline
Camping Ground could be pitched into Champion Hurdle fray at Cheltenham
Jer's Girl team want Spring showers at Leopardstown
Road To Riches heads Irish Gold Cup possibles
Nicky Henderson has Peace And Co steeled for Sandown
JLT option open for Garde La Victoire at Cheltenham
Albert Bartlett remains top Cheltenham target for Barters Hill
2 February 2016National Stud closed to public due to equine virus
Taunton winner Bloody Mary in good spirits for Nicky Henderson
Willie Mullins mob-handed in Deloitte at Leopardstown
Martin Keighley happy to wait with Festival-bound Solstice Star
Brian Ellison planning Musselburgh trip with Always Resolute
Cannon Fodder set for National Spirit date at Fontwell
Evan Williams eyeing Paddy Power for King's Odyssey as he takes long-term view
Cheltenham announce Festival handicap declaration changes
Simonsig team face crucial period
Leicester gets the go-ahead
Philip Hobbs salutes Captain Chris as he heads for retirement
More Of That to miss Sandown and wait for Kempton or Newbury
Change of plan means Ar Mad to take left-handed test at Plumpton
Cheltenham 'very doubtful' but Flemenstar in great heart after Tied Cottage run
Death of Punchestown great Risk Of Thunder, aged 27
Neil Mulholland - Shantou Village destination totally down to the ground
Seeyouatmidnight headlines informative Towton Chase at Wetherby
Noel Meade has Road To Riches firmly on track for Irish Gold Cup
Warren Greatrex retains faith in World ruler Cole Harden