Officials say the man went missing in the Dry Creek Canal near Abby Street and Olive Avenue just after 6:30 a.m. Sunday.
A battalion chief with the department says the man was first seen in the water near the train tracks on Olive Avenue.
At one point crews spotted the man underwater but the quick current swept him away.
Officials are now switching their search to a body recovery operation.
You're asked to avoid the area as they expand their search.
Stay with ABC30 for the latest details on this developing story.