The massive landslide in Oso, Wash., has shined a national spotlight on the damage this kind of natural disaster can cause.
But geologists say they don't have comprehensive data on landslides in most places. In fact, the most frequently cited statistic on landslides in the U.S. is out of date.
You may have heard the statistic: Landslides cause $1- $2 billion in damage every year and kill between 25 and 50 people. It's listed on the U.S. Geological Survey's website. It's used by FEMA and state agencies. It's been quoted in countless news reports about the Oso slide.
That statistic comes from a National Research Council paper. And that paper is almost three decades old.
“And the reason is, there's been no money out there to do current studies,” says Scott Burns, a geologist with Portland State University. He says it's not just a lack of nationwide data on deaths or economic loss. There's also no one monitoring where landslides happen -- at least, not at the national level.
Some states, including Washington and Oregon, are using laser technology called LiDAR to create detailed maps showing landslide-prone areas. But they're ahead of most states. Idaho hasn't updated its Landslide Inventory Map since 1991.
Experts say another problem with not having current information about the cost of landslides in the U.S.: it's very difficult to buy landslide insurance.
The 1985 report is by the National Research Council's Committee on Ground Failure Hazards. It's titled “Reducing Losses from Landsliding in the United States.” Scholars who cite the report often translate the 1985 financial cost into contemporary dollars, $3.5 billion or so.
But it's not based on any new data about landslides.