The Facebook posts started Wednesday morning with a warning.

About 8:30 a.m., word came that a semi had flipped near the Mullan Trail Exit on Interstate 90, east of Coeur d’Alene. The hill was foggy, the Facebook post warned.

“A diesel just flipped over on its side just before Cda… Emergency vehicles have not arrived… So it’s going to be backed up! Super foggy through that area,” Dan’s Tattoo Shop in Wallace posted.

“Heads up,” someone posted a little while later, adding a photograph of a semi trailer on its side.

“The drivers are safe,” Susie Yount of Silverton added. “We [saw] it happen.” She stopped at the scene to check on the truck driver and passenger.

What might initially have seemed like a routine accident and subsequent brief delay was something else. The traffic delay morphed into what one Facebook writer called a “five-hour drive from hell.”

It wasn’t routine at all, according to Megan Sausser of the Idaho Transportation Department.

“It was a very unique situation,” Sausser said.

The problem was the cargo.

The westbound rig was transporting syrup when it flipped. As workers from Superior Towing in Coeur d’Alene attempted to move the mess, they encountered another sticky problem. Syrup from broken containers inside the trailer began leaking onto the road, slickening the highway surface.

“At that point, it covered one lane and the spill was small,” Sausser said.

By about 10 a.m., the semi was still on its side. Workers had put down flares.

By 3:30 p.m. both lanes of westbound traffic were closed. Traffic was backed up to Beauty Bay, one Facebook user reported.

And then, about 4:30 p.m., according to the Idaho Transportation Department, as workers attempted to permanently clear the wreckage from the road, all hell broke loose. Traffic that had been moving slow as — well — molasses, ground to a stop.

“There was 10 inches of syrup at the median, and it covered all four lanes,” Sausser said.

Motorists who had waited since late afternoon were afforded no respite. Traffic would not freely move until midnight and crews would continue to work into Thursday to clean up what was described by an Idaho State trooper as “The Tapioca Syrup Crash.”

Ryan Gaddy of Pinehurst, who around 7 p.m. was stuck in traffic in the dark behind a Penske truck, wrote, “Do not approach CDA... 3rd hour not moving. Isp said truck keeps getting more broken up everytime they try to move it. Westbound lane is clogged for the foreseeable future and nothing is being done to divert traffic. No warning flares... nothing... don’t do it. Stay home!”

As motorists and passengers including children who had waited in their cars for hours without moving and were required to relieve themselves on the side of the road became more and more irate, workers used a variety of means to ensure the road was safe for cars and trucks.

“There is no manual on how to clean up syrup,” Sausser said.

Crews returned Thursday to clean the block of road marked by orange cones and 45 mph speed limit signs.

“There is still a giant patch of ice from the spill westbound yesterday,” Jennifer Gilley wrote. “When you see the construction signs to slow to 45 mph, slow down. At 45, I still slid. It’s like glass.”

But the ire of motorists who were stalled for hours the night before hadn’t been tempered.

“It never ceases to amaze me, when there is a horrific accident that ties up the pass the powers that be let everyone sit,” DiAnna Bechler Macklin of Post Falls wrote. “Why could they not take care of incident w/emergency personnel. identify approx time of shut down … move barriers, fill in the center and take care of the ever increasing line of cars. Turn them around. If they can change lanes in a heart beat for construction they can do this. Also shut down the on-ramp that are leading into this snafu.”