Heavy storms in California signify return of El Nino

On Tuesday, construction crews began fixing the highway bridge washed out by heavy weekend rains in California. Scientists say such rare summer storms are a preview of a potentially record-breaking wet winter in the west. NASA climate scientist Josh Willis says the storms are fueled by the phenomenon called El Nino.

"A whopper of an El Nino could bring a lot of really heavy rain really quickly, which brings as many problems as it does solutions," he said.

El Nino is a band of warmer than usual water in the Pacific Ocean, along the equator, that changes weather patterns worldwide. Forecasters say this one has the potential to be the most powerful on record.

Signs of El Nino have been washing up on western shores. Millions of red crabs carried north by warm water currents covered beaches. And starving sea lion pups are being rescued because the fish they eat have fled to colder water.

"This warm water stretches all the way from Baja all the way up to Alaska," said Shawn Johnson, a veterinarian at the Marine Mammal Center.

Four years of drought have led to massive wildfires, but El Nino-fueled storms could simply give way to massive floods.

Could this be a case of be careful what you wish for?

"We absolutely have to be careful what we wish for," said Willis. "Southern California, we're prone to floods."

A relatively small El Nino in 2005 brought down a hillside burying a neighborhood. The extreme 1997-1998 El Nino caused more than $4 billion in damage and killed 189 people nationwide.

If this El Nino continues to grow, we could see heavy rains here in California as early as next month, lasting throughout the winter. As one scientist put it, great droughts usually end in great floods.