The huge dust storm in Phoenix on July 5, 2011 started with rapidly descending air moving outward from area thunderstorms - combined with a lot of available dust.
Professional astronomers captured footage of an expanding light bubble over Hawaii, but it took the combined efforts of citizen astronomers to shed light on its cause.
The NOAA 2010 State of the Climate report tracks 41 indicators, each one including thousands of measurements that allow scientists to identify overall trends. Read more about one of the hottest years on record.