SNOHOMISH COUNTY -- Searchers are still looking for at least 11 people believed missing in the deadly Oso mudslide more than two weeks after the disaster.
In some places, the sludge is dozens of feet deep which makes search dogs critical in finding victims. Twenty more FEMA dog teams from across the country are now in Oso ready to help.
The dogs are trained to find a specific scent, and when they do they are rewarded.
These dogs are training now, but they have been instrumental in the search for victims in the Oso slide, but it hasn't been easy.
"It's very difficult, it's very stressful on them," said FEMA dog handler Sally Dickinson. "They're clamoring over stuff, they're getting stuck in the mud."
Dickinson and her Border Collie "Fielder" have scoured disaster sites all around the world. The landslide in Oso has been one of her most challenging.
"When you stand back and look at the geographic size of the event, it's breathtaking," she said.
The mud is so deep in spots it can bury the scent the dogs are searching for. The debris, made up of destroyed trees and homes, can also hide it. But these dogs are relentless -- often working 8 hours a day with their noses to the ground.
"It's obviously painstaking work... to go through and smell and smell and smell," Dickinson said. "And that really is what wears them out the most I think."
Handlers say the dogs are being tested to their limit and still finding success, and helping bring closure to victims' families.
Search teams say there is no timetable for how long they will be in the slide area searching for victims.