From tornadoes to blizzards, severe weather batters parts of the US

Tornadoes, thunderstorms and blizzard conditions are forecast to pummel parts of the eastern US.

More than 34 million people were under tornado watches from Florida to New Jersey.

Nearly 3ft (0.9m) of snow has fallen in Minnesota, Wisconsin and northern Michigan since the storm began this weekend, according to the National Weather Service (NWS).

The bulk of the storm is expected to churn off the east coast into the Atlantic by Tuesday, with abnormally cold weather to follow in its wake.

Over 11 million people are under blizzard warnings, and another four million are under winter storm warnings, according to the BBC's US partner CBS.

By Monday evening, nearly 4,600 flights had been cancelled and almost 11,300 delayed, according to flightaware.com.

The bulk of the flight cancellations and delays were at Chicago's O'Hare International airport and LaGuardia in New York.

More than 406,000 customers were without power, a third of them in Michigan, followed by Virginia and North Carolina.

In Minnesota, over 25in (63.5cm) of snow fell in parts of the state by Monday morning. More snow and strong winds were forecast.

"Whiteout conditions are expected and will make travel treacherous and potentially life-threatening," the NWS said.

Minnesota Governor Tim Walz has authorised the state's National Guard to support emergency operations, CBS said.

Severe thunderstorms were expected in parts of North Carolina, South Carolina and West Virginia, where NWS has predicted hail and "a tornado or two possible".

Tornado warnings were issued between 10:00 and 11:00 local time in parts of northern Virginia. A similar warning was issued for parts of the Florida panhandle.

In North Carolina, where wind gusts on Monday were predicted to exceed 74mph (119km/h), Governor Josh Stein encouraged residents to enable emergency alerts on their phones.

Schools in Raleigh and Chapel Hill, North Carolina, were closed on Monday. Schools were also closed in some districts in Wisconsin and Minnesota.

In Washington DC, park officials announced that the Washington Monument will close early at 13:00 local time as the storm drew closer.

"Beware of possible flash flooding, standing water, strong wind, lightning and hail," the Park Police said in a statement on X.

A tornado watch was issued for the US capital.

Canadians were also facing severe weather on Monday, particularly in central Ontario and south-western Quebec. Forecasters in the region predicted up to 20in of snow with wind speeds up to 49mph, warning of "near zero visibility" in some areas.

On the US west coast, an extreme heat watch was scheduled to go into effect for parts of southern California, Arizona and Nevada later this week.

Temperatures in southwest Arizona were expected to reach up to 109F (42C). Officials there warned of a "significant increase" in the chance of heat related illness.

On Wednesday, Phoenix could have its earliest day of temperatures exceeding 100F in nearly four decades.

The high temperatures and dry, windy pattern was also expected to increase wildfire danger across parts of the West and High Plains.

Over the weekend in Nebraska, roughly 30 National Guard troops were deployed to combat multiple wildfires, the state's emergency management agency said.

Nearly 1,000 sq miles (1,609 sq km) had already been damaged as of Saturday, the agency said. At least one fire-related fatality was reported.

A storm that soaked Hawaii over the weekend has shattered rainfall records dating to 1951, including nearly 24in of rain in Maui.

With its widespread impacts, forecasters say this could be one of the most significant weather events to hit the US so far this year, potentially affecting roughly 200 million people across multiple states.