The United States Geological Survey's (USGS) statement that a phenomenon called atmospheric river (AR) caused disastrous high winds and rains in northern California in October triggered a flare-up of fear among anxious residents about massive natural calamities waiting in the wings.

What perhaps spooked the people was a bit of history thrown the USGS press release which suggested that storms of proverbial might technically recur.

The Survey's 'ARkStorm' storm scenario has given rise to fears of a plausible super storm that researchers say would damage one-fourth of the state's buildings and houses, if it happens.

The storm scenario says such super storm has potential to move water of almost 50 Mississippi Rivers into the Gulf of Mexico, causing massive floods and devastation in California.

ARkStorm is a hypothetical winter storm scenario created by USGS's Multi-Hazards Demonstration Project for Southern California (MHDP) where experts have tried to forecast and assess the scientifically plausible physical event of a disastrous storm and the consequential secondary hazards as well as physical, social, and economic consequences.

The hypothetical winter storm scenario would impact the US West Coast and be analogous to the intense California winter storms of 1861-1862, providing a reality check on what is historically possible.

The storm scenario is named, ARkStorm to represent an atmospheric river (AR) with a value of 1000 (k) Ð on a scale of atmospheric rivers being devised by atmospheric scientists. The scenario storm then will be an AR 1000, and other US West Coast storms will be scaled in comparison.
USGS has said one of the purposes of the creation of the ARkStorm scenario was to address storms of this magnitude and help prepare emergency responders and resource managers.