All clearance above "0" water (MLLW or CRD datum) - Check NOAA for adjustment to the current Columbia River level or Willamette River level.
When navigating the Willamette River, call the Hawthorn Bridge first as it is manned 24/7 and also can tell you the clearances of the other 3 bridges. Bridges will not be opened during rush hours and you need to call at least 2 hours in advance for an opening on weekdays from 8:00am to 4:30pm, and 4 hours notices at all other times. The Broadway, Burnside and Hawthorn are all manned during the Rose Festival. For further details, check Multnomah County's Requesting A Bridge Opening.
