A small plane crashed in the Mississippi River near Ramsey on Friday evening, and a woman pulled from the water died, the Anoka County Sheriff’s Office said.

Lt. Brent Erickson said authorities do not yet know how many people were aboard the plane, which appeared to be a single-engine Cessna, when it struck power lines near the 6400 block of Riverdale Drive NW. around 5:35 p.m.

Witnesses who called 911 reported the plane was flying low — at or below the treetops — and heading upriver when it hit power lines stretched across the river and “did a nose-dive into the river,” he said. According to witness statements, the plane did not appear to have engine trouble.

“Why the pilot didn’t see the power lines or why he was flying low … we are unsure,” Erickson said.

Several witnesses got into their pontoons and rendered aid, pulling the woman from the water. She was pronounced dead at the scene by paramedics, Erickson said.

Emergency personnel have gathered some debris and have an idea of where the plane is in the river. They are planning to have divers search the river Saturday, but high water levels and the rapid current could hamper recovery efforts, Erickson said.

Officials have not determined the plane’s departure point or destination.

Investigators are reviewing video of the crash to confirm the number on the tail of the plane, Erickson said. The plane was believed to be a four-seater.

The woman’s identity was unknown Friday evening.

Lora Hamilton, 83, of Ramsey, said she was having supper at her home near the river when she saw the low-flying plane.

“It was below tree height,” she said. Then she heard the crash.

Multiple power lines were down after the crash, said Adam Jachymowski of Ramsey-based Connexus Energy.

About 540 consumers in Ramsey and north Dayton were briefly without power, he said.

Power was restored shortly before 7 p.m.