SEATTLE — Expect heavy traffic on the roads and in the water this weekend for the official start to boating season.

Lane reductions on northbound Interstate 5 on the Ship Canal Bridge this weekend and the complete closure of the Montlake Bridge on Saturday could bring about big delays for drivers.

Both lanes of traffic on the Montlake Bridge will be closed Saturday, May 4 from 10 a.m. - 4 p.m. for the opening day of boating season. 

The boat parade will run through the Montlake Cut, meaning the drawbridge will be up to make room for the many masts that will go through. 

The boating day tradition can be traced back to 1913 when the waterway opened Lake Washington to Lake Union. The Windermere Cup is also this Saturday.

Two lanes of northbound I-5 on the Ship Canal Bridge will be closed Saturday and Sunday from 3 a.m. - 11 a.m. The East Roanoke Street on-ramp to northbound I-5 will be closed on Saturday only.  

WSDOT crews will be repairing the bridge deck this weekend.

RELATED: Know the risks on the water this boating season

RELATED: Boaters get pre-season safety reminders as temps rise