By Keith Coffman

DENVER (Reuters) - The Colorado county where a three-mile-wide mudslide roared through the Grand Mesa National Forest declared an emergency on Wednesday, after dangerous conditions prompted authorities to suspend a search for three ranchers presumed dead in the disaster.

The slide occurred on Sunday outside the small town of Collbran, about 200 miles west of Denver.

Mesa County Sheriff Stan Hilkey said on Tuesday that it was unlikely the men survived, and that shifting ground and water buildup behind the vast debris field has made it hazardous for crews to enter the area.

“It’s unsafe and not stable to do the search we would like to do,” he said.

If the pooling water breaks loose, areas below the slide could be inundated, Mesa County commissioners said. The emergency declaration, set to be ratified next week, will free up federal and state resources to gauge the threat.

“This declaration is largely being done to assess the risk, since we don’t have the expertise or the jurisdiction to fully support the assessment,” county administrator Tom Fisher said in a statement.

A deep snowpack and several days of rain-weakened terrain in the forest set up the catastrophe, and when the mountainside gave way, a 250-foot-deep wall of timber, mud, snow and dirt tore through the valley, authorities said.

The missing men, local cattle ranchers, were identified as Clancy Nichols, 51, his son Danny, 24, and Wes Hawkins, 46.

They had gone up the mountain on Sunday morning to investigate damage done to irrigation ditches from an earlier slide when a sodden ridge gave way, the sheriff said.

The men's families have been told that when the ground search resumes, likely this summer, it will be a recovery rather than a rescue effort, he said.

Hilkey said crews will continue to do aerial searches using infrared equipment designed to detect heat sources for any sign of the men or their vehicles.


(Editing by Cynthia Johnston and Gunna Dickson)