SEATTLE — In the weeks before the Oso mudslide, Shari Brewer and her husband noticed a change in the bluff that towered over the North Fork of the Stillaguamish.
A crack at the top of the slope was widening, but it didn’t seem like anything to be alarmed about. “It was just sliding down a little,” said Brewer, who lives west of Darrington. “It wasn’t a lot, but we could see that it was opening up.”
Jeffrey Moore isn’t surprised.
Large landslides don’t strike out of the blue, said the University of Utah geologist. Unstable slopes almost always creep, slough and sag long before they let loose. Monitoring that movement can provide lifesaving warnings, though the approach is rarely used in the Northwest.
“I don’t know why we don’t invest more in trying to pre-empt these disasters,” said Moore, before correcting himself.
“I do know why.”
Monitoring is costly. Few states have enough funds to even identify the most treacherous slopes.
In Switzerland, a landslide-prone hill like the one that collapsed and killed at least 30 people on March 22 would have been wired with sensors and surveyed at least twice a year for signs of movement, said Moore.
That country’s vigilance has averted multiple disasters in narrow, alpine valleys, where residents evacuated to safety before major slides came crashing down.
Kennecott’s Bingham Canyon copper mine in Utah sent workers home and relocated equipment the morning of April 10, 2013, based on monitoring with state-of-the-art radar and other methods. Later that day, a massive slide thundered through the pit.
“The technologies are out there,” Moore said. “This is something that people should really speak up for.”
But budgets for landslide work are “at the bottom of the pile” when it comes to geologic hazards, said Portland State University Professor Scott Burns.