As the search for missing persons in the aftermath of a massive mudslide in Washington enters its second week, some searchers will be taking a much-needed break. Rescue dogs, who have been essential in the search for victims of the mudslide that hit Oso, Wash., on March 22, will be getting some rest after working long hours in the cold and rain, rescue crews said Sunday. The dogs can lose their sensing ability if overworked, officials said, according to the Associated Press. “The conditions on the slide field are difficult, so this is just a time to take care of the dogs,” said Kris Rietmann, a spokeswoman for the team working on the eastern portion of the slide. Dogs from the Federal Emergency Management Agency that arrived more recently will continue working, said Heidi Amrine, another spokeswoman for the operation. Late Saturday, authorities revised the number of people believed to be missing from 90 to 30, while the official death toll edged up to 21. Below, a look at some of the search and rescue dogs at the site.