"The weather conditions are challenging," said Petty Officer 1st Class Robert Cox in a statement. "We have trained crews responding and on scene searching for any signs of the helicopter and those aboard."
The owner of the helicopter raised the alarm about the aircraft at 6:06 p.m. (11:06 p.m. ET), according to the statement. The helicopter carrying one pilot and six passengers, which had been touring of Kauai's Napali Coast, had been due back at 5:21 p.m.
While the aircraft is equipped with an electronic locator, no signals had been received, according to the Coast Guard.