article_snippet: A drought in the western United States has left water levels in the Colorado River basin far below A drought in the western United States normal levels.
article_snippet: the Colorado Colorado provides water for Nevada, Arizona and California, the last of which has seen large areas in 'extreme' and 'exceptional' drought levels and is trying to restrict how much water residents use.
article_snippet: Sections of extreme drought have hit many states of the southwestern United States, including Arizona, Colorado, Nevada and California .
article_snippet: This map shows the severity of the drought in the western US, with 'exceptional' drought in dark red, 'extreme' drought in red and 'severe' in orange.
article_snippet: Drought levels are based off precipitation and moisture indices .