On July 18, 2015, about 2045 Pacific date time, a Kubicek Hot Air Balloon, N938BS, impacted the ground hard after an approach to a dirt field at Hidden Valley Lake, California. The balloon was operated by Sonoma Thunder Inc., Sebastopol, California, as a Visual Flight Rules (VFR), revenue sightseeing flight under the provisions of Title 14 Code of Federal Regulations Part 91, when the accident occurred. Visual meteorological conditions prevailed, 16 passengers and the pilot were not injured, and three passengers were seriously injured. The balloon came to a stop after its second impact with the ground. The pilot reported that he was landing the four burner hot air balloon in variable wind conditions, and he "deliberately made firm contact with the ground", in order to avoid power line wires and trees. During the landing, the basket impacted the ground, bounced approximately 20 feet in the air for a distance of 50 feet to the north-northwest, where it impacted again and remained in contact with the ground. The pilot stated, "When the balloon landed after the bounce, the passengers were caught off guard, and some of the passengers fell on top of each other". Three of the passengers were treated for serious injuries. The hot air balloon was not damaged. The pilot opined, "Both of (the) contacts with the ground were hard but not abnormal and quite similar to deliberate or aggressive landings made during my past piloting experiences."