An expanding winter storm has hit the US states of Arkansas, Tennessee and Kentucky with snow, sleet and freezing as Washington, DC, and much of the east coast braced for blizzard conditions could drop up to 76cm of snow.
The Dublin Airport Authority has said that four departure flights from Dublin Airport to the east coast of the US tomorrow morning have been cancelled.
The cancelled flights are United Airlines flight to Newark, an American Airlines to Philadelphia, an Aer Lingus flight to New York and a Delta Airlines flight to New York.
Meanwhile one Aer Lingus flight flying from New York to Dublin has also been cancelled.
Passengers flying from Shannon Airport on a British Airways flight this evening and a United Airlines flight tomorrow morning are advised to contact the airline.
The US National Weather Service described the storm as "potentially crippling" for a swath of the northeast, with up to 61cm of snow due to hit the Baltimore and Washington metro areas.
A blizzard watch was issued for New York City and parts of its Long Island and New Jersey suburbs starting early tomorrow.
Snow accumulation could reach 30cm in the region, forecasters said.
Southeastern Pennsylvania, including Philadelphia, was expecting 25 to 42cm of snow.
Governors of Arkansas and Tennessee ordered state offices closed as the storm dropped 13cm of snow in Arkansas and snow, sleet and freezing rain was spread across northern Tennessee and south-central Kentucky.
Across the southeast, government offices, schools and universities were shut.
Millions of residents in the storm's path scrambled to prepare, picking stores clean of bottled water, food and other supplies.
Consumer watchdogs warned against illegal price gouging for essentials such as generators, batteries, flashlights as well as hotel rooms.
Federal employees in the Washington area allowed to leave early before the snow begins piling up and public schools were shut.
The Washington Metropolitan Area Transit Authority, which includes the second-busiest US subway system, took the rare step of suspending operations from late today until Sunday.
The Virginia National Guard said it planned to bring in up to 300 troops to assist in response operations.
Airlines have also cancelled more than 5,000 flights, most of them at airports in North Carolina and Washington, according to FlightAware.com.
Philadelphia's airport said it would cancel all flights scheduled for tomorrow.
Washington Mayor Muriel Bowser and New York Mayor Bill de Blasio urged motorists to stay off roads amid icy and whiteout conditions.
Many of you will wake up with snow covered roads this morning! Before you head out, check https://t.co/7aWkixP6ql!— AR State Police (@ARStatePolice) January 22, 2016
Ms Bowser said the nation's capital was better prepared for the coming storm than it was for the sudden snowfall that left scores of motorists - including President Barack Obama - battling gridlock on Wednesday night.
"We can and will do better for this storm. Even with that, this is a historic storm and so we're putting all of our resources at it," she said.
Given the extraordinary conditions expected, the city has been preparing all week for the type of blizzard that Ms Bowser said the Washington has not seen in 90 years.
AccuWeather senior meteorologist Alex Sosnowski said the storm could bring one of the biggest snowfalls on record, eclipsing the "Snowmageddon" storm of 2010 that dropped 45.2cm.
The largest snowstorm recorded in Washington was the 1922 Knickerbocker storm, which buried the city under 71cm of snow.