Authorities say flood concerns have eased in the San Luis Valley of southern Colorado because of a steady runoff from gradually warming weather.

But state officials warn that rivers could still overflow if warm weather coupled with rain accelerates the spring melt of deep mountain snow.

Mike Sullivan, an engineer for the Colorado Division of Water Resources, says nighttime temperatures are still dipping below freezing this spring, which helps keep the runoff in check.

Rio Grande County authorities had warned residents earlier this year to be alert for possible floods because of heavy snow last winter.

Sullivan says state and local governments made sure they had equipment and plans in place.