California - one of the driest states in the US - is being inundated with torrential rain and flooding. And given the decades-long drought in the region, which has led to restrictions on water usage in some areas, you might be wondering if this extreme weather could in some ways be a positive. But the downpour is unlikely to have a big impact on the drought. In fact, experts say it would take consecutive years of severe wet weather to reverse it in the long-term.