But about an hour after the water supply was cut off, engineers inspected the viaduct and found no damage. Traffic was allowed back on the major arterial by 5 p.m.
The water main break sent a geyser of water spewing under the viaduct at about 3:15 p.m. Tuesday. Crews were able to shut off the water supply within 45 minutes, but in the meantime hundreds of thousands of gallons of water flooded the area.
Aerial footage from KOMO's Air 4 also showed floodwaters from the broken main surging through the streets of University Village before crews were able to shut off the water supply.
Seattle Fire Department spokesman Kyle Moore said the break was in a major one-foot water main near NE 45th Street and 25th Avenue NE.
Seattle police shut down 45th Street between 22nd Avenue and Montlake Boulevard for about 1 1/2 hours, as pools of standing water lapped at the base of the pylons supporting the structure. Thousands of vehicles use the viaduct each day, and it is a major arterial used by commercial vehicles and buses.
Long lines of traffic backed up in the vicinity as commuters scrambled to find alternate routes.
None of the shops in University Village were flooded, however the standing water could affect gas lines and electrical lines to the shops, along with sprinkler systems, Moore said.
For a time, the decreased water pressure also was setting off fire alarms in buildings at the University of Washington.
There was no immediate word on what caused the break.