Jennifer Chu, MIT
On Dec. 11, 2014, a freight train of a storm steamed through much of California, deluging the San Francisco Bay Area with three inches of rain in just one hour. The storm was fueled by what meteorologists refer to as the “Pineapple Express” — an atmospheric river of moisture that is whipped up over the Pacific’s tropical waters and swept north with the jet stream.
By evening, record rainfall had set off mudslides, floods, and power outages across the state. The storm, which has been called California’s “storm of the decade,” is among the state’s most extreme precipitation events in recent history.
Now MIT scientists have found that such extreme precipitation events in California should become more frequent as the Earth’s climate warms over this century. The researchers developed a new technique that predicts the frequency of local, extreme rainfall events by identifying telltale large-scale patterns in atmospheric data. For California, they calculated that, if the world’s average temperatures rise by 4 degrees Celsius by the year 2100, the state will experience three more extreme precipitation events than the current average, per year.