Police say Dylan Collins and Isaiah Loring left a facility in Westbrook and may be in the Lewiston-Auburn area.

Experts and environmental advocates say the long-term impact on fish and other river life is hard to predict, and could depend on what happens next.

Officials are trying to determine if the area in Westbrook is safe for engineers and work crews to begin shoring up the bank and restoring the river’s flow.

The National Weather Service issued a flash-flood watch for areas downstream of the slide, but the river appeared to be at least partially flowing within hours.