On July 8, 2007, at approximately 1430 central daylight time, a twin-engine Boeing 737-800 transport category airplane, N929AN, operated by American Airlines Incorporated as Flight 488, encountered unforecasted clear air turbulence during the climb to cruise altitude near McAlester, Oklahoma. One flight attendant sustained serious injuries and the other 2 flight attendants sustained minor injuries. The two pilot and 99 passengers were uninjured. No reported damage was sustained by the aircraft. An instrument flight plan was filed and visual meteorological conditions prevailed for the scheduled international passenger flight operating under provisions of Title 14 Code of Federal Regulations Part 121. Flight 488 originated at the Dallas Fort Worth International Airport (DFW) at 1356, and was destined for the Lester B. Pearson International Airport (CYYZ) near Toronto, Canada (CYYZ). In a written statement provide to the NTSB, the captain reported encountering moderate clear air turbulence while the airplane was climbing through 30,000 feet mean sea level (FL300). The captain further reported that "the seat belt sign was on and all passengers were seated at the time." Both the captain and the first officer had monitored the weather radar, and neither detected any weather anomalies. The three flight attendants in the cabin area were performing crew duties when the unexpected turbulence was encountered. One flight attendant hit her head on the forward wall of flight class section. The second flight attendant was performing duties in the aft gallery and sustained a cut and bone contusion to her right hand, and sprained her neck, back and hand. The third flight attendant, who was also in the aft galley, reported that she hit her left foot resulting in a bone fracture. At 1353, an automated weather observation station located near McAlester, Oklahoma reported winds from 150 degrees at 9 knots, visibility 10 statute miles, scattered clouds at 4,500 feet with a ceiling of broken clouds at 5,000 feet, temperature 89 degrees Fahrenheit, dew point 71 degrees Fahrenheit, and a barometric pressure of 29.90 inches of Mercury.