It was the worst railroad disaster in American History. And it happened in our own backyard.

"It's probably the best-kept secret as far as disaster go," says Don Moody, the leading authority on this disaster.

There are no monuments or memorials that commemorate what happened here in the Cascade Mountains. But if you know where to look, you'll find evidence of an old and grievous tragedy.

In 1910, this grassy plateau near Stevens Pass ski area was home to a small railroad town called Wellington. The dusty road nearby once held train tracks - the tracks of the Great Northern Railway.

In Late February of 1910 - a year that saw the Cascades wracked by a series of ferocious blizzards - the weather turned so nasty that the railway was impassible.

Hundreds of workers were sent out to clear the tracks, but they couldn't keep up with Mother Nature.

"It was snowing so hard that they couldn't see ahead of them, they couldn't see in back of them," says Moody. "It was just a white-out."

For an entire week, a Seattle-bound passenger train was blocked at Wellington, as avalanches thundered down ahead and behind them. Worried passengers begged train officials to back the train into the safety of a nearby tunnel.

Train officials refused, saying the tunnel was so cold that they'd have to burn too much fuel to keep warm.

It proved to be a fatal mistake.

Just before 2 a.m. on March 1, an electrical storm passed overhead.

Says Moody: "One eyewitness, a guy by the name of Charlie Andress, saw the bolt of lightning slam into the side of the mountain, saw it looked like what he said half the side of the mountain coming down on his train."

The avalanche sent three trains tumbling down the mountain side - the passenger train, a mail train and a private train belonging to the railroad superintendent.

Rescuers found just 18 survivors - and 118 people were found dead.

The town of Wellington was wiped off the map soon after, and in 1929, the tracks were torn up and moved a half mile south.

Rusted remnants of the train still exist - a reminder of this sad and little-remembered chapter of Northwest history.

There's a new book about the avalanche that's just been released called "The White Cascade: The Great Northern Railway Disaster and America's Deadliest Avalanche" by Gary Krist.