Replacing the collapsed bridge over I-5 in Mt. Vernon will take “months, not weeks” according to State Senator Kevin Ranker, who briefed county and town officials at a hastily organized “emergency meeting” of the San Juan County Council the day after the 55 year-old bridge crashed into the Skagit River May 23 in Mount Vernon.

That timetable caused consternation for local officials, concerned that the first months of the tourist season on the islands might see significant disruptions for travelers trying to reach the San Juan Islands. The U.S. Army Corps of Engineers is working to locate a suitable “Bailey bridge” to temporarily replace the fallen span, but any solution won’t happen until mid-summer at the earliest, according to Ranker.

“Alternate routes can get travelers to the Anacortes ferry dock with only a few minutes of additional drive time,” Councilman Rick Hughes said.

After speaking with Governor Jay Inslee early on the day after the collapse, Hughes said the governor understood the problem and promised that the Department of Transportation would get to work “immediately” on necessary signage to guide travelers to Anacortes without having to drive through the Mount Vernon area.

Local officials circulated electronic maps showing alternative routes for travelers to take to reach the ferry landing in Anacortes to the local media less than 24 hours after the bridge plummeted into the Skagit River. The Memorial Day weekend has long been thought of as the unofficial start of tourist season in the San Juans.

Friday Harbor Mayor Carrie Lacher said she’d used alternate routes many times, including taking the Mulkiteo-Clinton ferry.

“Both locals and tourists will enjoy the scenic routes whether coming from the south or the north,” she said.

Emergency Services Manager Brendan Cowan said he was in touch with air, rail and water transportation providers, and all indicated they would step up to provide additional services as needed.

Ranker said early estimates indicate repair of the bridge may cost $15 million.

Todd Banks of Kenmore Air, which during summer months flies some 7,500 passengers per month to the islands utilizing both land-based and seaplanes, said they would add reserve planes to regularly scheduled routes if the number of advance reservations warrants more daily capacity.

“We’ve done this many times on busy summer routes,” Banks said, “and we’re ready to assist our valued San Juan Islands customers in their time of need.”

The collapse was apparently caused when a giant over-sized steel girder being transported on I-5 whacked a load-bearing arch at full speed, according to San Juan County Superintendent of Public Works Frank Mulcahy, a civil engineer who offered an “off the cuff” assessment at the Friday afternoon briefing.

“Our state bridge engineer is looking into the possibility that an oversize load may have struck the bridge. Still investigating,” the Washington State Department of Transportation tweeted on Thursday night.

The 1,111-foot, steel-truss bridge was built in 1955, according to the nongovernmental website nationalbridges.com, which offers a searchable database of the National Bridge Inventory compiled by the Federal Highway Administration. It was built before the freeway for U.S. 99.

The database classifies the Skagit River bridge over I-5 as “functionally obsolete,” which indicates the design is not ideal, but it is not rated as “structurally deficient.”

“’Functionally obsolete’ does not communicate anything of a structural nature,” according to nationalbridges.com. “A functionally obsolete bridge may be perfectly safe and structurally sound but may be the source of traffic jams or may not have a high enough clearance to allow an oversized vehicle.”

In 2010, according to the database, the bridge carried an average of 70,925 vehicles per day. The substructure was deemed in “good condition,” and the superstructure and deck were described as in “satisfactory condition.”

The federal database says a structural evaluation of the bridge found it “somewhat better than minimum adequacy to tolerate being left in place as is.”

According to a 2012 Skagit County Public Works Department, 42 of the county’s 108 bridges are 50 years or older. The document says eight of the bridges are more than 70 years old and two are over 80.

That there were no fatalities “is a miracle,” said Ranker, who explained that emergency personnel were on the scene within minutes and the three people in the water were quickly retrieved from the river and transported to local hospitals and treated. According to Ranker, “everything went perfectly.”