Snow storms are threatening travel across many US states over the Thanksgiving holiday.

A warning of “significant travel disruption” was issued by the Foreign and Commonwealth Office ahead of Thanksgiving Day today (Thursday).

About a quarter of 1,500 flights scheduled at Denver international airport were cancelled on Tuesday with other services threatened.

The US National Weather Service (NWS) published blizzard and wintery weather warnings from the Rocky Mountains to the Great Lakes.

The impact is expected to be felt across New England as well as New York City while another storm is brewing on the west coast states of Oregon and California.

Up to six inches of snow is expected across New Hampshire and Maine accompanied by strong winds.

The NWS forecast “very windy conditions likely on Thanksgiving across much of the north-east along with much cooler temperatures compared to the previous days”.

It added: “In addition to the heavy snow potential with the western area of low pressure, heavy rains are also a threat at lower elevations with flash flooding threats for southern California through Thanksgiving Day, spreading eastward into the south-west by early Friday morning.”

Delta Air Lines said its meteorologists are monitoring a winter storm moving across the Rockies into the US Midwest with travel waivers “proactively issued” for Denver and Minneapolis.

The airline said: “The storm will continue to trek east through mid-week, bringing winds and frozen mixed precipitation through parts of the Midwest.”

Delays from de-icing operations are likely, Delta added.

The FCO said in updated travel advice: “Heavy snow is disrupting travel across the centre of the United States causing significant travel disruption over the Thanksgiving holiday period, including a number of cancelled flights.

“If you are due to travel to or within the US in the coming days you should check with your airline before travelling.”

US airlines expect to carry 31.6 million passengers over the 12-day Thanksgiving travel period between November 22 and December 3.

Sunday, December 1, is expected to be the busiest day with more than 7,000 flight departures scheduled.