On Friday, Governor John Hickenlooper declared a disaster emergency for 14 counties from the Wyoming border to Colorado Springs. President Obama also declared a federal state of emergency for Boulder, Larimer, and El Paso counties, allowing FEMA to deploy four rescue teams to those areas.
This afternoon, Reuters reports that a fifth victim, a 60-year-old woman who was swept away by flood waters, is now missing and presumed dead.
Unlike other recent flooding disasters in countries like Taiwan and China, Colorado's defies expectation. September tends to be a drier month for the state, reports National Geographic.
Sandra Postel, National Geographic's Freshwater Fellow, tells the magazine that the flooding may be linked to recent droughts, which have hardened the soil of the Colorado River Basin, preventing it from absorbing much of the rainfall. Forest fires may also shoulder some of the blame; a portion of the vegetation normally responsible for trapping rainwater burned to the ground in recent years.
"It will take climate scientists many months to complete studies into whether manmade global warming made the Boulder flood more likely to occur, but the amount by which this event has exceeded past events suggests that manmade warming may have played some role by making the event worse than it would have otherwise been."
News and social media outlets are updating pictures regularly. What follows are some of the most striking.