DARRINGTON, Wash. — Crews searching through the muck and devastation wrought by Washington’s deadly mudslide are finding more human remains, bringing the official death toll to 24.

Seventeen of those 24 victims have been positively identified, the Snohomish County medical examiner’s office said Monday afternoon. Previously, the official death toll was 21, with 15 victims identified.

More than two dozen people remain missing, authorities have said.

Steve Harris, a division supervisor for the search effort, said search teams are learning more about the force of the March 22 slide, and that is helping them better locate victims in a debris field that is 70 feet deep in places.

“There’s a tremendous amount of force and energy behind this,” Harris said of the slide. He didn’t provide further details.

Harris said search dogs are the primary tool for finding remains in the small, mountainside community about 55 miles northeast of Seattle. He said searchers are finding human remains four to six times per day. A makeshift road completed over the weekend links one side of the 300-acre debris field to the other.

Searchers have had to contend with treacherous conditions, including household chemicals, septic tanks, gasoline and propane containers. When rescuers and dogs leave the site, they are hosed off by hazardous materials crews.

Gov. Jay Inslee on Monday asked President Barack Obama for a major disaster declaration in Snohomish County to make programs available to help individuals, households and businesses.

Last week, a federal emergency declaration was approved that provided a federal disaster team and specialized personnel to the slide area.

Members of the Seattle Seahawks football team and Seattle Sounders soccer team were scheduled to visit with community members Monday evening.