A business invitor has a duty to exercise reasonable care to prevent injury to an invitee, but an invitor owes no duty to protect against hazards which are open and obvious. Williams v. Tulsa Motels, 1998 OK 42, 958 P.2d 1282, 1284. Williams quoted City of Tulsa v. Harman, 1931 OK 73, 148 Okla. 117, 299 P. 462, 468, for the long-standing rule: The invitee assumes all normal and ordinary risks attendant upon the use of the premises, and the owner or occupant is not liable for injury to an invitee resulting from a danger which was obvious or should have been observed in the exercise of ordinary care. Williams involved a slip and fall on a wet floor. In that case, the plaintiff observed a hotel maid mopping the floor before he fell. The court concluded that it was clear from the evidentiary material that the plaintiff knew or should have known the floor was wet. In Williams, the hazard was created by the innkeeper. In Buck v. Del City Apartments, Inc., 1967 OK 81, 431 P.2d 360, the hazard was ice and snow. the Supreme Court held: It is clear from the evidence that the wife knew or should have known of the general weather conditions. the dangers from them are universally known and were equally as apparent to her as they were to the motel keepers. There is no evidence here that the usual hazard from the icy condition was in any way increased by an act of the motel keepers. Where there is no act on the part of the owner or occupant of the premises creating a greater hazard than that brought about by natural causes, dangers created by the elements, such as the forming of ice and the falling of snow, are universally known, and all persons on the property are expected to assume the burden of protecting themselves from them. The Supreme Court noted the rule that there is no duty to warn an invitee of any defect or danger which is well-known to the invitee or which is obvious, or which should have been observed by the invitee in the exercise of ordinary care. Id. at 343, citing 65 C.J.S. Negligence, 50. The court concluded that because the plaintiff knew it was raining and knew the condition of the premises based on prior use, the wet floor of the kitchen was as known to the plaintiff as it was to her parents, so that the parents had no duty to warn and therefore were not negligent. Id. The court affirmed the trial court's decision sustaining the defendant parents' demurrer to the evidence.