Washington governor: Mudslide a square mile of "total devastation"; 18 missing

A wide aerial view shows the extensive damage of the landslide after taking out a chunk of earth from the side of the hill facing the Stillaguamish River, and down into the State Route 530, on the left, between the cities of Arlington and Darrington, on Saturday, March 22, 2014. Search and rescue operations are underway for survivors. (AP Photo/ The Seattle Times, Marcus Yam ) (The Associated Press)

An aerial view of the Stillaguamish River leading up to the landslide, above, that shows a huge volume of earth missing from the side of a hill, along State Route 530 between the cities of Arlington and Darrington, on Saturday, March 22, 2014. (AP Photo/ The Seattle Times, Marcus Yam) MANDATORY CREDIT TO BOTH THE SEATTLE TIMES AND THE PHOTOGRAPHER (The Associated Press)

Washington Gov. Jay Inslee described the scene of a deadly mudslide that killed three people as a square mile of "total devastation" after flying over the disaster area Sunday.

The governor assured families at a news briefing that every endeavor is being explored to find their loved ones.

Eighteen people were unaccounted for a day after a terrifying wall of mud and debris destroyed as many as 30 homes in rural Washington state.

Inslee says "there is a full scale, 100 percent aggressive rescue going on right now."

Authorities said that because of the quicksand-like mud, it was too dangerous to send rescuers into the stricken area. Searchers were flying over the area in helicopter looking for signs of life.

The governor urged residents in nearby communities to remain alert to possible flooding.