The pilot reported that he was departing from a helipad and all cockpit instrument indications were "in green" status. Wind was very calm to none and the pilot verified it by looking at two flags on an offshore vessel. Another aircraft took off from the helipad and departed to the east. The pilot hover taxied to the west of the flight area with a right petal turn. He rechecked the instruments, which were "all normal." He added power and the flight was normal as the helicopter was climbing. The helicopter was about 40 to 50 feet over a roadway and it started to settle. He added more power and it looked as if it was going to recover. Then the helicopter started to sink again. There were occupied trailers under the helicopter and obstacles blocking a nearby field. The pilot elected to head left of course for less impact with anything on the ground or with property. The helicopter impacted terrain where it sustained substantial tailboom and fuselage damage. The pilot reported that the helicopter was within weight and balance requirements and that there were no mechanical malfunctions. Following the impact, he noticed that the previously observed flags were now showing the wind was blowing and gusting from the southwest direction.