Punchestown under threat
The meeting at Punchestown on Sunday is subject to an inspection on raceday morning, as are the British fixtures at Fakenham and Hereford.
All are threatened by the cold snap, with officials at Punchestown and Fakenham taking a look at 8am and Hereford being checked out half an hour later.
Punchestown is due to stage the boylesports.com Tied Cottage Chase, which features a clash between Champion Chase winner Big Zeb, Golden Silver and Sizing Europe.
The course is currently raceable and the official going is soft, but there is a possibility of a severe overnight frost.
Overnight temperatures at Fakenham dipped to minus 3C and another frost has been forecast.
Clerk of the course David Hunter said: "I think we're in with a fighting chance. We would have so nearly raced today, but the ground is too tight and crusty in places.
"The forecast is encouraging, however, and we're pretty confident it's not going to be as cold as Friday night."
Hereford is covered by a protective fleece, but overnight temperatures are again due to dip well below freezing.
Clerk of the course Keith Ottesen said: "It's a bit crispy on the surface and under the covers, but it's only a surface frost. It's been cold for a long time, though, so we would want improvement before it freezes again.
"The longer it stays above freezing, the better. If everything heads in the right direction we should be OK."