SANTA ROSA (CBS SF) – Sonoma County residents are girding themselves for closed streets and traffic jams during the Ironman swim, bike and run race Saturday.

The event starts with a 2.4-mile, 2-lap swim in Lake Sonoma between 6:40 a.m. and 7:10 a.m.

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Racers will then leave Santana Drive in Cloverdale for a 112-mile, 2-loop bicycle ride through the Alexander, Russian River and Dry Creek valleys from 8-10 a.m.

The last portion of the triathlon is a 26.2-mile, 3-loop run along the Santa Rosa Creek Trail between Fulton Road west of Santa Rosa and Courthouse Square in downtown Santa Rosa.

The runners should start finishing the marthon and arriving in downtown Santa Rosa at 3 p.m., but non-professional athletes still arrive between 10 p.m. and 12 a.m. Sunday. The event closes Sunday with an awards breakfast at the Ironman Village in downtown Santa Rosa.

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Road closures will be in effect 11 a.m. to 11 p.m. in some areas Saturday. Closures are planned in downtown Santa Rosa, 13 Santa Rosa neighborhoods and portions of 11 more roads in the unincorporated area of northern Sonoma County and Windsor.

Santa Rosa police are advising motorists to plan for extra travel time.

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