Flooding in a Parched Landscape

Over the past week, an atmospheric trough developed off the California coast, sweeping Pacific moisture across that parched landscape.  Within a few days, many regions of the State received more precipitation than they had in all of 2013.

Falling on slopes ravaged by wildfires, the steady rains triggered floods and mudslides while, in some urban areas, storm drains could not handle the deluge, stranding motorists and producing sinkholes.  Welcome snows fell across the Sierra Nevada and Transverse Ranges but rapid runoff limited the storm system's benefit at lower elevations.

A significant dent in California's severe, multi-year drought will require recurrent Pacific storm fronts throughout the winter months.  The current atmospheric trough (produced by a dip in the jet stream) is already moving on and meteorologists remain uncertain whether an El Nino pattern will take hold; that oceanic and atmospheric phenomenon would favor the development of recurrent storms in the coming months as the waters of the eastern Pacific begin to warm.  By contrast, a La Nina pattern is characterized by high pressure off the California coast, driving warm surface water and moist air to the west and shunting storm systems northward into Canada and Alaska.  Californians are certainly hoping for a boy this winter!