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Scale of California drought calculated

Scientists have assessed the scale of the epic California drought and say it will require more than 40 cubic km of water to return the US State to normal.

The figure was worked out by weighing the land from space.

The American West Coast has been hit by big storms in recent days, but this rainfall is only expected to make a small dent in California's problems.

Jay Famiglietti from Nasa's Jet Propulsion Laboratory (JPL) in Pasadena, California, described the current drought conditions to our correspondent Jonathan Amos.

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