#arkstorm

THE ARKSTORM COMETH

Once upon a time, Central Valley of California became a lake when it was flooded in what is termed an “Arkstorm.” Yes, that’s right, a storm huge enough to require an Ark to survive.

Though this name “ARkstorm” brings about mental images of Noah and all the animals lining up to board an oversized wooden barge, the initial letters “AR” stand for “Atmospheric River.” An atmospheric river is a swath of water vapor-rich atmosphere that can stretch for thousands of kilometers. To paraphrase F.M. Ralph, it’s an airborne river flowing toward you at 30 miles per hour that contains more water than 7–15 Mississippi Rivers combined. In the case of California, an atmospheric river can begin in the tropics of the South Pacific, then flow east all the way to the coast, trapped within atmospheric layers.

Imagine this river hitting the mountains of California, head-on. That is when an Arkstorm occurs, causing massive flooding. In the flood of 1861-1862, Los Angeles received 1.65 meters (66 inches) of rain, and the Central Valley became a Central Sea reaching a depth of more than ten meters with flooding conditions lasting for six months. Geologic studies show that these sorts of mega-floods happen once every one hundred or two hundred years in California, with or without the aid of global warming.

Global warming? With rising temperatures, there will be more water vapor in the atmosphere, and (as for mega-hurricanes) a higher chance for the formation of the kind of atmospheric river that can cause a super storm. If you don’t live in California, don’t feel left out: atmospheric rivers can emanate from the Gulf of Mexico and cause deluges in Tennessee, or in the South Atlantic and pour out over Britain and the rest of Europe.

Today, the California Department of Water Resources (http://www.water.ca.gov/floodmgmt/) hopes that their dams and levees can control this kind of flood, but the system has yet to be tested by a real Arkstorm.

Perhaps in the future of our climate-confused world, California will be drowning.

Annie R