Two truck drivers died Wednesday in a pre-dawn, chain-reaction pileup of five tractor-trailers on icy Interstate 90 between Alberton and Superior.

The deadly crash also resulted in injuries to a third driver and a fireman from Frenchtown Rural Fire District, one of several agencies called to assist Mineral County responders. Both were hospitalized in serious but not life-threatening condition.

The initial report of the crash came into Mineral County dispatch shortly after 4 a.m. Interstate traffic in both directions was blocked for most of the day by jackknifed trucks and lumber strewn across the eastbound roadway.

Traffic was diverted onto the East Mullan frontage road between Exit 47 at Superior and Exit 61 at Tarkio. The Montana Department of Transportation reported the crashes occurred at mile marker 47.6, just west of the Quartz Creek Rest Area at a railroad crossing bridge.

Capt. James Kitchin of the Montana Highway Patrol said westbound flow resumed at about 3 p.m. but one vehicle remained blocking the eastbound lanes Wednesday evening. Besides the wrecked tractor-trucks and lumber on the highway, there was damage to the bridge deck and rail that wouldn’t be easily repaired. One lane through the accident scene was expected to be opened by 7 p.m.

Trooper Terry Rosenbaum of the Montana Highway Patrol said the drivers involved were all males, all were headed eastbound toward Missoula and all five semis remained upright in the end.

The drivers of the second and fifth trucks died. Their identities weren’t released.

The sequence of crashes began when a semi-truck slid broadside as it approached the bridge, dumping its flatbed load of lumber. It came to a stop with the trailer and spilled lumber blocking both eastbound lanes. The driver and passenger escaped unharmed.

A couple of minutes later, the next oncoming tractor with a UPS trailer veered to its left to avoid the first one, Rosenbaum said. It went across the median, cleared the guardrail with the exception of the rear right wheels of the trailer and came to a stop diagonally blocking the westbound lanes.

“The driver … got out of his vehicle and stood in front of it in the westbound lane,” Rosenbaum said.

The driver of an approaching truck told Rosenbaum he was able to brake and maintain control. But he watched as the driver of the wrecked truck, thinking he would be hit, “bailed to his left over the bridge rail, falling approximately 40 feet to his death,” Rosenbaum reported.

A third eastbound truck slammed into the trailer of the first one near the bridge. That driver was partially ejected and had to be transported first to Mineral Community Hospital in Superior and then by air to Kalispell Regional Medical Center. Rosenbaum said Wednesday afternoon the man was in serious condition but talking in the Kalispell hospital.

Another truck, the fourth, “slid into that mess,” but its driver wasn’t hurt, Rosenbaum said.

The final truck slammed into the trailer of the fourth rig. That driver was the second fatality.

All the crashes came long before daylight, on a stretch of I-90 that was reporting black ice conditions well into Wednesday morning, though temperatures remained several degrees above freezing throughout the night. Rosenbaum said it was neither raining nor snowing at the time of the crashes.

Mel Holtz of Frenchtown Fire said his department received a request for assistance just before 5 a.m. The injured firefighter was among the first from Frenchtown to respond. He slipped on the ice and tumbled over the bridge deck. He was transported to a Missoula hospital with serious but what Holst called “non-life threatening injuries at this point.”

Holst was among the responders to the scene.

“I stepped out and it was sheer ice,” he said. “The whole bridge deck and before and after were icy.”

It was the third morning in a row that winter driving conditions plagued traffic in western Montana. Schools in the Bitterroot Valley from Florence to Hamilton postponed classes for two hours Wednesday morning. MDT reported severe driving conditions on U.S. Highway 93 and the Eastside Highway between Florence and Stevensville.