Saturday’s high-profile fixtures at Ascot and Haydock will have to pass inspections if they are to go ahead.
Ascot’s card features the Grade 1 LK Bennett Clarence House Chase, but the Berkshire track has been unraceable since Tuesday morning and clerk of the course Chris Stickels will hold a 4pm inspection on Thursday to assess the prospects of racing.
He said: “We are currently unraceable, the track is frozen in places. It is even frozen in places under the frost covers.
“We were not raceable at all yesterday, despite temperatures getting up to 5C during the day.
“It got down to -1.75C last night and we want to see if there is any improvement today.”
Haydock is due to stage four Grade 2 events, including The New One Unibet Hurdle and Peter Marsh Chase.
However, the Merseyside venue was hit by snow overnight, prompting clerk of the course Kirkland Tellwright to call a noon inspection on Friday to assess whether racing can go ahead.
He said: “We have had half an inch of snow overnight with a frost, so things are not looking as good as they were.
“We have called an inspection for noon tomorrow and we would need to see the snow gone by then if we are to persevere.
“It depends on which forecast you look at – on the most optimistic it’s just about feasible, but on the most pessimistic we will be beaten.”