PORTLAND, Ore. — Traffic could see some extra slowdowns around the Interstate Bridge within the next week due to rising levels on the Columbia River resulting in more frequent bridge lifts, according to the Oregon Department of Transportation (ODOT).
At the crossing, the Columbia River level is usually between six and seven feet. By early next week, it's expected to rise above 15 feet. The flood stage at that point on the river is only 16 feet.
The result will be longer and more frequent lifts of the bridge spans, as both upstream and downstream-bound ships will need to use greater caution in navigating the fast, swollen river.
Bridge lifts can sometimes be completed in six to eight minutes, ODOT said, but the current conditions mean they will last up to 20 minutes at a time.
"The increased river level has reduced the clearance at the high span, which is at the hump in the bridge at mid-river," the agency said. "That causes more marine traffic to use the lift span along the north side the river. More lifts bring more delays on I-5."
Maritime law dictates that marine traffic take priority over traffic on I-5, but there are exceptions for the height of the weekday commute. No lifts are allowed from 6:30 a.m. to 9 a.m. and again from 2:30 p.m. to 6 p.m. on weekdays, except federal holidays.
A wet spring for the Columbia River Basin has contributed to the high water levels, and KGW's team of meteorologists forecast much more within the next several days.
An atmospheric river arrived Thursday evening, kicking off a stretch of on and off rain through the weekend that will extend this year's exceptionally cool and rainy spring season in the Portland area.
Models show Portland picking up an additional half to three-quarters of an inch of rain from late Friday afternoon through early Saturday.
To the north, the National Weather Service has said that June’s unusual heavy rainfall, late mountain snowmelt and runoff could cause some western Washington rivers to sharply rise with minor flooding possible in some areas.
Water levels on the Columbia crossing like these aren't precisely common, but not unheard of either. ODOT reports that the Columbia reached the flood stage at the Interstate Bridge in 2017, topping out at 18 feet, and reached 19 feet in 2011. The highest level in recent memory was in 1996, when the water level reached 24 feet.