NORMAN, Okla. — Operators of a central Oklahoma casino say they had no time to alert guests before a possible tornado tore off part of its roof and caused a deluge of rain to pour inside.

State emergency managers were surveying damage at the Riverwind Casino in Norman on Sunday after the overnight storms pushed through the state.

Casino spokeswoman Kym Koch says the possible tornado hit the facility at the same time the National Weather Service issued a tornado warning for the area. The possible twister hit during a Beach Boys concert inside that was attended by Gov. Mary Fallin.

Koch says no one was injured.

She says the casino has no electricity and parts of the property are closed off while repairs are made. The casino has canceled reservations through at least Tuesday.

Emergency managers and the National Weather Service are surveying damage from storms that spawned as many as four tornadoes in southwest Oklahoma.

No injuries have been reported.