Washington state Governor Jay Inslee was among several hundred people who have gathered for an interdenominational prayer service honouring the victims, families and rescuers affected by the deadly March 22 mudslide in Oso.

Hanging at the front of the Haller Middle School gym where the service took place on Friday night was a large banner that simply said Together.

Clergy involved in planning the Arlington event wanted to reflect the connection among neighbours not only in Oso but in nearby Arlington and Darrington, KING-TV reported.

The audience twice gave standing ovations to first responders who continue to search the debris for missing people.

“Nobody, and I mean nobody, could be prepared for what we encountered,” Arlington Fire Chief Bruce Stedman told the crowd.

As of Friday, the toll stood at 30 people dead and 13 missing in the landslide that buried the community of Oso, about 90km northeast of Seattle.

“I’ve walked away many times, saying to myself, ‘Why, God, why?”‘ said chaplain Ralph Fry.

“And what I do know today is that God’s love sustains us in the darkest moments of our lives.”

Four private memorial services are scheduled this weekend for victims, slide response officials said in a statement.