HONOLULU — As the first tropical storm to hit Hawaii in 22 years passed by the islands, some coffee farmers on the Big Island began navigating flooded roads to assess damage to their crops Friday while tourists wandered the beaches of Oahu and surfers took to the waves despite driving rain and wind.
The first storm in a one-two punch heading for Hawaii clamored ashore overnight Friday as a weakened tropical storm. A second system close behind it also weakened and was on track to pass north of the islands by several hundred miles.
Tropical Storm Iselle knocked out power, caused flooding, and downed trees when it crossed onto the Big Island. There have been no reports of deaths or major injuries, Governor Neil Abercrombie said Friday.
About 21,000 homes were without power on the Big Island, where the main part of Iselle came ashore in a rural and sparsely populated region, Hawaii County Civil Defense spokesman John Drummond said. Those staying in shelters were told to return home, while crews cleared trees from roads, county spokesman Kevin Dayton said.
The Department of Health warned the public to stay out of floodwaters and storm water runoff across Hawaii because they are known to attract sharks.
Heavy rains and wind from the storm’s outer bands also hit Maui and Oahu on Friday as Iselle moved west, but it went south of the other islands.
Honolulu’s lifeguard division said about a dozen surfers were riding waves Friday at a spot nicknamed ‘‘Suicides,’’ near the popular Diamond Head crater. Lifeguards on Oahu were planning to only respond to emergency calls, avoiding regular patrols.
Back on the Big Island, coffee farmers on the southeastern side tried to get around fallen trees on flooded roads to determine any crop damage, said Randy Stevens, general manager of Kau Coffee Mill.
‘‘It’s raining so hard we’re just trying to get the roads opened up so we can get to the fields,’’ Stevens said.
The storm affected some Big Island residents who planned to vote in Saturday’s primary election. Officials say they will postpone the election for about 8,000 voters in two precincts on the island because of road damage.
The roads left communities in Puna isolated, Chief Election Officer Scott Nago said in a statement Friday.
The rest of the primary will move forward as planned, and the two precincts will vote absentee later, Nago said.
The heavy rain and flooding seen in the southeastern Kau district were vastly different from the relatively drier Kona region on the Big Island’s western side, where much more coffee is grown, and the storm had little impact.
‘‘We’re all buttoned up, but nothing happened,’’ said Bruce Corker, a Kona coffee farmer.
Meanwhile, Hurricane Julio, some 900 miles behind, was downgraded to a Category 2 storm and packed maximum sustained winds of about 105 miles per hour. National Weather Service officials predict it will continue to weaken on a path that should take it about 200 miles north of the island chain starting Sunday morning.
If Julio stays on track, ‘‘the impacts to the islands would be minimal,’’ Weather Service meteorologist Derek Wroe said. ‘‘We would see some large surf. ... We could see some heavy showers.’’