First Avenue Bridge
Bascule drawbridgeFirst Avenue Bridge is a bascule drawbridge with 22 ft of clearance closed, measured to mean high water. Its open clearance is not charted.
Clearances are from NOAA chart US5WA15M, measured to mean high water. Actual clearance is lower whenever the water stands above that level, as at higher tides and in storm surge. Always confirm against your vessel's air draft and the posted clearance gauge before transiting.
Pathr nautical charts
First Avenue Bridge on the chart
Find the bridge and its charted vertical clearance in one view. Select a pin to compare nearby bridges, see open and closed clearances where charted, and open its operating details.
How to request an opening
the draws of the First Avenue South Bridges, mile 2.5, need not be opened for the passage of vessels from 6 a.m. to 9 a.m. and from 3 p.m. to 6 p.m., except: The draws shall open at any time for a vessel of 5000 gross tons and over, a vessel towing a vessel of 5000 gross tons and over, and a vessel proceeding to pick up for towing a vessel of 5000 gross tons and over.
Source: US Coast Guard drawbridge regulations, 33 CFR 117.1041 (Duwamish Waterway). Confirm before transiting.
Frequently asked
What is the clearance under First Avenue Bridge?+
First Avenue Bridge is a bascule drawbridge with 22 ft of clearance closed, measured to mean high water. Its open clearance is not charted. These figures are from NOAA chart data. Real clearance drops whenever the water stands above the level they are measured to, so leave a margin for your air draft.
How do I get First Avenue Bridge to open?+
Contact the bridge tender on VHF-FM, or sound the required signal. Operating schedule: the draws of the First Avenue South Bridges, mile 2.5, need not be opened for the passage of vessels from 6 a.m. to 9 a.m. and from 3 p.m. to 6 p.m., except: The draws shall open at any time for a vessel of 5000 gross tons and over, a vesse
Tides & conditions at this crossing
Clearance under First Avenue Bridge shrinks as the water rises. Check the water level and marine conditions at the nearest NOAA station, Duwamish Waterway, Eighth Ave. South (1 mi away).
