Gallery: Shocking scences from Colorado as death toll begins to rise
Already hit by the worst floods seen in decades, residents in Colorado are bracing themselves for more rain as the death toll currently sits at four and 172 people unaccounted for.
Some of the footage from Boulder and nearby towns is nothing short of incredible where flash floods have toppled buildings, washed out roads and inundated farmland.
Flooding began on Wednesday and search and rescue teams have used boats and helicopters to pull stranded residents to safety and those efforts have been stepped up with so many people still unaccounted for.
The National Weather Service in Boulder warned of scattered showers and thunderstorms later on Saturday and into Sunday that could trigger further flash flooding in the already drenched area and is the worst flooding in the state since nearly 150 people were killed in Larimer County in 1976 by a flash flood along the Big Thompson Canyon.