‘Scientists consider Sacramento — which sits at the confluence of the Sacramento and American Rivers and near the delta — the most flood-prone city in the nation. Experts warn that there are two events that could destroy the levees and set off a megaflood. One is an earthquake; the second is a violent Pacific superstorm, like the one called the Pineapple Express, which sweeps water off the ocean around Hawaii and dumps it on the mainland with firehose intensity while battering the coast with high wind and waves. A megaflood would not arrive as gradual seepage; it would be a rapid submerging of hundreds of square miles.’
via Sacramento Levees Pose Risk to California and the Country – NYTimes.com.