Friday afternoon's meeting at Doncaster must pass a second course inspection at 9am.
Although the track was raceable at 8am, more snow has been forecast ahead of the first Flat fixture on turf this year.
Clerk of the course Roderick Duncan said: "We are currently raceable, but I can't call it.
"There is more green out there than there is white, but we are expected to get more snow."
Doncaster's big meeting on Saturday, featuring the William Hill Lincoln, must now pass an inspection at 12pm this afternoon.
Duncan has moved forward his intended check from 8am on Saturday morning.
