Southern California braces for flooding, storms, hail, tidal surges and tornadoes

Authorities and residents were bracing for flooding, thunderstorms, hail, tidal surges and even small tornadoes Wednesday as the worst of a seven-day series of storms was expected to sweep into Southern California.

Wednesday's storm was projected to be the most intense of the week, the result of a powerful, cold storm from the Gulf of Alaska colliding with a river of subtropical moisture from the western Pacific Ocean.

"When you get the very cold air mixing in with the very warm air, it can be quite volatile," said Bill Patzert, a climatologist at the Jet Propulsion Laboratory in La Cañada Flintridge. Forecasters said the system could produce lightning and possibly waterspouts offshore and small tornadoes on land, Los Angeles Times reports.

California residents should brace themselves for the most severe of an ongoing series of storms to hit the state, forecasters have warned.

More than 12 inches of rain have fallen in parts of the Santa Monica Mountains in the south and up to 15.5ft of snow has accumulated at Mammoth Mountain ski resort over the last four days.

And the conditions are expected to worsen in the next few days, the National Weather Service has warned, with the possibility of thunderstorms, hail and even tornadoes and flash floods, Daily Mail reports.