A wildfire on Santa Rosa Island, which started Friday, reached 5,690 acres Saturday afternoon.

U.S. Coast Guard spokesman Richard Uranga confirmed to Noozhawk that a 67-year-old man on a sailboat ran aground on rocks on Santa Rosa Island in the Channel Islands National Park sometime late Thursday night or early Friday morning.

The man was not injured. There were no other people on board the sailboat at the time.

Uranga initially said Friday that the man had fired flares into the air to “try and get help, which is what caused the fire.”

In an email on Monday night, he clarified that the Coast Guard “cannot confirm the cause of the fire” and said the cause was still under investigation by the National Park Service.

The man was rescued from the island Friday morning around 10:30 a.m. and taken to the Camarillo Medical Center, per Uranga.

The fire was 0% contained as of Saturday afternoon.

The fire was reported in a “remote section of the island,” according to CalFire.

“Moderate fire behavior was observed overnight with terrain-driven runs,” a CalFire spokesperson said Saturday morning.

No structures were reported damaged or threatened.

Check back with Noozhawk for updates.

For the record: This article was updated to include additional comments from Uranga.