On April 1, 2019, about 0757 Pacific daylight time, a Cameron Balloons US, A-400 hot air balloon, N6954YA, was not damaged when it was involved in an accident near Napa, California. The pilot and 18 passengers were not injured, one passenger sustained serious injuries and two passengers sustained minor injuries. The balloon was operated as a Title 14 Code of Federal Regulations Part 91 sightseeing flight. The pilot reported that, about 10 minutes into the flight, and about 500 ft, the wind changed direction and the balloon entered a downdraft. The pilot added heat to compensate for the descent and level flight was established. The balloon’s basket subsequently contacted a power line. After the pilot attained a slow ascent, the power line released from the basket, and the pilot immediately landed the balloon in a field without further incident. The pilot reported that there were no preaccident mechanical failures or malfunctions with the balloon that would have precluded normal operation.