0n April 5, 2003, at approximately 2015 mountain standard time, an Airbus Industrie A319-111, N917FR, owned by Frontier Airlines, Inc., and operating as flight 133, encountered turbulence near Pueblo, Colorado. The captain, first officer, one flight attendant, and 59 passengers were not injured. However, one flight attendant was seriously injured and one received minor injuries. The airplane was not damaged. Visual meteorological conditions prevailed. The scheduled domestic passenger flight was being operated on an instrument flight rules flight plan under the provisions of Title 14 CFR Part 121. The flight originated at 1945 from Denver, Colorado, and was en route to Dallas, Texas. The captain stated that the airplane was climbing when they encountered light turbulence at 22,000 feet over Pueblo, Colorado. One of the pilots called to the flight attendants and asked them to sit down. According to the captain, 30 to 60 seconds later the airplane encountered severe turbulence. One flight attendant fractured two metatarsal bones in her left foot, and another flight attendant received minor injuries. The airplane returned to Denver without further incident. The weather packet, issued by the company and ATC reported that nothing more than light turbulence was to be expected. There were no returns on the radar in the immediate vicinity of Pueblo, Colorado.