A powerful storm known as a nor'easter battered the US east coast, causing power outages, flooding, high winds and hazardous ocean conditions. At least one person was killed in New York City, and hundreds of thousands were left without electricity across the region. The storm struck the mid-Atlantic and New England over the weekend, and was forecast to continue into the early part of the week, while local officials in New Jersey and New York told residents that high tides in the week could potentially bring more flooding. Eight counties in New Jersey remain under a state of emergency.

• Nor’easter storm batters US east coast with heavy winds and power outages

Powerful weather system pummels shoreline for a second day, knocking out power to tens of thousands

Residents of coastal communities in the US’s north-east slogged through floodwaters for a second day as a powerful storm known as a nor’easter pummeled the shoreline on Sunday, knocking out power to tens of thousands of homes.

Tidal surges swamped low-lying neighborhoods in New Jersey while wind gusts toppled trees on New York’s Long Island, damaging homes and bringing down utility poles.

The ocean phenomenon could raise sea levels by up to a foot as El Niño keeps warm water trapped along the coast

Concerns are mounting about an ocean phenomenon known as a Kelvin wave that could raise sea levels along the California coastline by up to a foot, as scientists say El Niño is supercharging the threat of storm surges and flooding in the coming months.

As an incredibly strong El Niño continues to develop in the Pacific, the phenomenon brings with it a strange shift in the ocean. The Kelvin wave phenomenon is created when trade winds that usually blow from South America towards Asia die down or reverse in El Niño years, setting off a massive, slow-moving slosh of water.