POWELL TOWNSHIP -- Update 5:18 p.m. EST

Search and rescue crews along with family and friends continued their search for a missing Big Bay woman.

Abby Johnson, 81, was last seen Wednesday morning when she apparently drove off in her son's white GMC pick up truck.

Johnson suffers from Alzheimer's disease.

Search and rescue crews from the state police, sheriff's department and Powell Township Fire Department have been searching for Johnson along with volunteers since Wednesday evening.

crews have been searching roads in vehicles and four wheelers and have even been using a plane.

So far they say they have not found any evidence leading to where Johnson could be.

"We've got a grid pattern search going on right now that goes out several miles from where she was last seen, the vehicle was last seen," said Lt. Robert Pernaski of the Michigan State Police.

Search and rescue crews will continue looking for the rest of the evening.

Friday they say they will re-evaluate their search strategy.

If you have any information, you can contact your local police.

Update 9:51 a.m. EST

The Civil Air Patrol is going to conduct an air search for Abby Ann Johnson, 81, who was reported missing on Wednesday.

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State Police are asking the public for help in locating a missing Powell Township woman.

They're looking for 81-year-old Abby Ann Johnson who has Alzheimer's disease.

She was with her son on Dodge City Road just off of Triple-A Road in Powell Township.

Police say Johnson was waiting for her son in his pickup truck when she drove off without him around 10 a.m. Wednesday.  She is 5'3", 150 pounds with hazel eyes and brown hair.  She was last seen wearing black pants.

Police are looking for a white 2000 GMC Sierra with a tan topper.  The license plate number is BUZ 7171.

Anyone with information is asked to contact police.