The US has seen various types of severe weather in recent weeks, with much of the country bearing the brunt of a winter freeze. However, California has been subject to relentless rain since the turn of the year and there is little sign of this easing over the coming week. This “atmospheric river” has brought successive areas of low pressure and exceptional rainfall to major cities on the west coast, with San Francisco seeing more than 250mm (10 inches) of rain over a 10 day period up to 4 January.
The resulting floods have already caused at least six deaths this year. Much of the precipitation has fallen as snow over the Sierra Nevada, with depths in the mountain range double what would be expected in early January.
