Container ships are stacking up off Southern California's congested ports, with the number of anchored vessels close to breaking the 2021 record despite the peak shipping season being in its early days.

Thirty-seven container ships were waiting near the ports of Los Angeles and Long Beach in recent days, according to the Maritime Exchange of California, the highest number since February, when 40 were anchored.

The situation comes as a flood of imports and logjams in domestic logistics networks hit operations at the biggest U.S. gateway for seaborne trade.

Port congestion is simultaneously building along the East Coast, with anchorage numbers off Georgia well into the double digits and, for the first time this year, a growing queue offshore of the Port of New York and New Jersey, Freight Waves reports.

Just a couple of months ago, the number of container ships at anchor in the two ports, which together handle more than a third of all U.S. seaborne imports, had dwindled to nine. In normal times, the number would be one or two, The Wall Street Journal reports.

Leaders of the two ports say the high number of cargo ships is due to surging volumes and unpredictability in global supply chains caused by the pandemic, and exacerbated by shippers pulling holiday-season imports forward to avoid delays later.

U.S. imports are bringing in carbo earlier "knowing that it probably will take longer to get it into their systems," Port of Los Angeles Executive Director Gene Seroka, was quoted as saying by the publication.

The Southern California congestion is one of a number of global bottlenecks as ports juggle strong consumer demand and shortages of workers and equipment caused by pandemic-related health and safety measures. Twice this year dozens of container ships had to wait at anchor in major Chinese ports because of slowdowns in operations after Covid-19 outbreaks.

After surging in the first quarter, congestion was capped by vessel supply. The more ships stuck at anchor, the fewer available to pick up export cargo in Asia, forcing carriers to “blank” (cancel) sailings Freight Waves reports. That dynamic eventually curbed the number of ships at anchor on the Southern California coast, and simultaneously, U.S. import capacity.

A key variable for the weeks ahead involves the COVID-induced terminal closure in Ningbo, China. As of Monday, the affected terminal had been closed for six days. When Covid-19 curtailed throughput in Yantian, China, in June, it gave Los Angeles/Long Beach a brief reprieve from inbound volume, reducing congestion temporarily, then subsequently increasing congestion as delayed Yantian cargo belatedly arrived.

Ship positioning data from MarineTraffic showed nearly 40 container ships at anchor off Ningbo on Monday. According to S&P Global Platts, “Port issues in China threaten to limit carrying capacity in peak season.”

On the East Coast, congestion has largely centered on the port of Savannah, Georgia, this year, driven at various times by high volume, weather closures of the Savannah River, and dredging.

As of Monday, MarineTraffic ship-positioning data showed 17 ships at anchor off Tybee Island, awaiting berths in Savannah.

According to Hapag-Lloyd, “Ships are delayed four to five days awaiting berth assignment. Berth congestion is not going to get better in the foreseeable future, with a minimum of 10 ships at anchor.” Hapag-Lloyd said that import loads are not moving out of the Savannah terminal fast enough, due to a shortage of chassis, trucks and warehouse space.

Meanwhile, ship-positioning data showed nine ships stuck waiting offshore of terminals in New York and New Jersey on Monday.