A motorcycle rider who witnesses say was popping a wheelie through the streets of Napa was in critical condition after colliding with a vehicle Sunday, Napa police said.

Witnesses said Chaz Baldwin, 22, of Napa was riding a Suzuki motorcycle at high speeds, at one point popping a wheelie, while headed west on 1st Street. As he approached McKinstry Street, he collided with a Toyota Highlander, driven by Kathy Atkinson, 62, of Salt Lake City. She was turning north onto McKinstry Street from the opposite direction on 1st Street, police said.

The collision sent Baldwin flying off the motorcycle and into a 1st Street building, police said.

He was taken to Queen of the Valley Medical Center for emergency treatment and was in critical condition as of Monday night, police said.

Police are still investigating whether alcohol was involved and the exact cause of the collision.

Witnesses are asked to call Officer Tom Helfrich at 257-9223.