Evacuations are underway across Hawaii’s Big Island and Maui as winds associated with Hurricane Dora, which is in the Pacific Ocean south of Hawaii, helped fan wildfires that have damaged structures.

Dora, a powerful Category 4 hurricane with sustained winds of 130 mph, was about 740 miles southwest of Honolulu as of late Tuesday (5 a.m. ET Wednesday), the National Hurricane Center said.

There were no hurricane watches or warnings in effect for Hawaii. Winds of 70 to 80 mph were recorded on the Big Island, Lt. Gov. Sylvia Luke told CNN.

Two brush fires were burning Tuesday on the Big Island, officials said in a news release, one in the North Kohala District and the other in the South Kohala District. Some residents were under mandatory evacuation orders as power outages were impacting communications, the release said.

The Upcountry fire is estimated to be about 1,000 acres, according to county officials. The cause of the fire was unknown.

Luke, who is acting as the governor as Gov. Josh Green is traveling out of the state, issued an emergency proclamation Tuesday, activating the Hawaii National Guard “to support emergency responders in the impacted communities.”

CNN’s Aya Elamroussi and Jamiel Lynch contributed to this report.