image source, Mario Tamaimage captionThe backlog means thousands of cargo containers are stuck at sea

A large backlog of cargo ships is stuck outside two of America's biggest ports, in the latest sign of the supply chain disruption hitting the US.

On Monday some 65 container ships were queuing outside the ports of Los Angeles and Long Beach, California, which handle almost half of all cargo containers entering the country.

Before Covid, it was unusual for more than one to wait for a berth.

It's linked to surging demand for imports as the US economy has reopened.

US retailers and manufacturers have rushed to place orders and restock their inventories, but the global shipping system has not kept pace.

Coupled with Covid disruptions, it's caused shortages of everything from children's toys and timber, to new clothes and pet food. It has also pushed up consumer prices.

Together, LA and Long Beach are the main seaborne gateway to the US, particularly for imports from China.

Some cargo ships have been diverted because of the backlog, but nearby ports like Oakland do not have the capacity to deal with the volume of trade.

  • Disruption to shipping could last until Christmas

Head of the Port of LA, Gene Seroka, last week warned of a "significant volume" of trade "headed our way throughout this year and into 2022".

"We continue to monitor a host of variables, disruptions continue at every note in the supply chain," he added.

Cargo volume at the Port of LA is up 30% this year to date, compared to the whole of 2020. And on Saturday a record 73 ships were stuck outside the port – almost twice as many as last month.

media captionCargo ships were forced to queue at the Port of Oakland in California in April 'Weather the storm'

The US Toy Association, which represents 950 toy firms with a US presence, has warned the crisis in California could affect many of its members going into the all important holiday season.

Its members sell three billion toys a year – 85% of which come from China.

"The larger retailers we work with have relationships with the shippers, and they can weather this storm fairly well relatively speaking," boss Ed Desmond said.

"It's really the small companies that are facing the brunt of this impact. They really don't have the leverage or the size to have those annual contracts."

The Californian ports have now agreed to expand the hours during which trucks can pick up and return containers to try to ease the backlog.

They are also working with the White House Supply Chain Disruptions Task Force, which was set up in June to try to alleviate trade bottlenecks.

Other ports such as Savannah and Georgia have also seen record shipping congestion, while the nation's second busiest entry point – New York – said it was facing transit issues outside the port.

"Currently congestion is related to cargo moving from the port, such as trucks and freight rail, due to record-high cargo volume," spokeswoman Amanda Kwan told the BBC.

Last month port bosses across the US told the Wall Street Journal they saw the bottlenecks lasting until summer 2022.

By tonnage, about 70% if all US-international trade moves by water through America's ports.