The balloon pilot reported that, during approach, he flew over a line of trees and noticed powerline wires. He told his 12 passengers to "get down," and he turned off the propane tanks in the basket, in anticipation of the baskets contact the powerline wires. In an effort to avoid powerline contact with the balloon's support cables, the pilot activated the burners on the opposite side of the expected contact point, in hopes of ascending. The balloon contacted the powerline wires just above the leather bolster, "causing a huge explosion." The powerline wires cut through the support cables in the pilot compartment. The balloon began to ascend away from the powerline wires, and the pilot maneuvered to a parking lot and descended to land. During descent, the balloon's basket caught fire. The pilot landed on the asphalt parking lot surface and the passengers exited the basket. The pilot rapidly deflated the envelope and the attempted to extinguish the fire. The balloon sustained substantial damage to the support cables and the basket. The pilot reported that there were no preaccident mechanical failures or malfunctions with the balloon that would have precluded normal operation.