Nearly 200,000 customers were without electricity in the western state of California, and nearly as many were affected in five northeastern states, the monitoring site poweroutage.us reported.

Along the upper Atlantic coast, heavy snowfall and wind toppled trees and blocked roads, local weather services said.

"Our utility crews... are working tirelessly to get everyone's power restored," New Hampshire Homeland Security and Emergency Management said on Facebook.

The agency warned residents to exercise caution, particularly while shoveling snow.

"If you have a history of heart problems, do not shovel," it said.

In Massachusetts, several school districts called for snow days, such as in Berkshire County, where up to 28 inches (71 centimeters) of snow fell.

"Additional 3-8 inches of snowfall can be expected over portions of New York and New England into Wednesday," the National Weather Service (NWS) said.

On the other side of the nation, new flooding from torrential rains hit California, the most populous US state with 39 million inhabitants.

"The atmospheric river will continue to impact California into Wednesday. This potent storm is expected to produce heavy mountain snow and gusty winds from the Sierra to the central/northern Rockies," NWS said.

This "atmospheric river" is a giant rain corridor that carries water vapor stored in the tropics, often around Hawaii, and has caused a particularly wet winter on the West Coast.

Since the weekend, the town of Pajaro south of San Francisco has dealt with flooded homes and vehicles after a levee burst Friday night, forcing thousands of people to evacuate the area.

Evacuation orders were also issued in Santa Barbara County in the southern part of the state, including parts of the upscale coastal enclave of Montecito, where Prince Harry and his wife Meghan live.