Originally Published: 12 JAN 24 06:55 ET

Updated: 12 JAN 24 10:22 ET

By Holly Yan and Robert Shackelford, CNN

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(CNN) — A calamitous cocktail of vicious winds, extreme snowfall, dangerous thunderstorms and potentially deadly cold is taking aim across the country as perilous conditions snarl travel and threaten power outages in freezing temperatures. Here’s the latest:

More than 66 million people are under winter weather alerts Friday: The alerts stretch from Oregon to New York.

LIVE UPDATES: Powerful winter storm set to wallop eastern half of the US

‘Life-threatening’ blizzard conditions: The vast majority of Iowa will be under a blizzard warning Friday into Saturday as 6 to 10 inches of snowfall gets whipped by wind gusts of more than 40 mph.

“Travel is expected to become dangerous by Friday morning. Blowing snow is expected to significantly reduce visibility to near-whiteout conditions by midday Friday persisting into early Saturday,” the National Weather Service in Des Moines warned.

“The cold wind chills as low as 10 to 20 below zero could cause frostbite on exposed skin in as little as 30 minutes and could be potentially life-threatening if stranded outside.”

Winds are expected to increase Friday morning, “with life threatening blizzard conditions expected into Friday afternoon and Friday night,” the National Weather Service office in Des Moines said.

Hundreds of record lows could be shattered: More than 240 daily cold temperature records could be tied or broken across the US through Tuesday.

Wind chills across parts of Montana could reach as low as -70 degrees this weekend. By Tuesday, the high temperature in Memphis, Tennessee, might reach only 17 degrees – which would set a new record.

Over the next week, more than 55 million people will endure temperatures below zero.

The East Coast could get deluged: At least 35 million people from North Carolina all the way up to Massachusetts are under flood watches Friday as more rain is expected to pound the East Coast – including some areas still trying to recover from the torrential downpours and storms that thrashed the region earlier this week.

Coastal flooding could submerge vehicles in the Northeast: More than 7 million people are under flood warnings across parts of the Northeast coastline. While New York City is under a coastal flood advisory Saturday, parts of Suffolk and Nassau counties could get hit with more severe coastal flooding — up to 3 feet above ground level in some places.

“This will result in extensive road closures and flooding of low lying property including parking lots, parks, lawns and first floors and basements of homes/businesses near the waterfront,” the National Weather Service office in New York said. “Vehicles parked in vulnerable areas near the waterfront will likely become flooded and/or submerged. Flooding will likely also extend inland from typical flood prone areas along the tidal rivers and bays, causing flooding in some areas that typically don’t see flooding.”

Philadelphia is under a coastal flood warning for much of Saturday, and Boston is under a coastal flood watch Saturday morning and afternoon.

Fierce winds and tornadoes could strike the South: More than 50 million people in the South are under a severe storm threat Friday. Parts of northern Alabama and Mississippi face the greatest risk for strong gusts, which could be accompanied by tornadoes or large hail.

Other Southern cities at risk for severe weather include Memphis, Charlotte, Atlanta, Raleigh, Birmingham, Jacksonville, New Orleans, Nashville, Virginia Beach and Tampa.

Millions are under tornado watches: More than 5 million people in Texas, Arkansas, Louisiana, Tennessee and Mississippi are under a tornado watch until 11 a.m. CT. The area includes Little Rock, Arkansas; Shreveport, Louisiana; and Jackson, Mississippi.

Flights are grounded: More than 1,000 flights to, from or within the US have been canceled for Friday, according to FlightAware.com.

What to expect in key cities

Chicago

Alert: A winter storm warning is in effect from 3 a.m. CT Friday until noon Saturday CT.

Snowfall: More than 8 inches of snow is expected, and snowfall rates could exceed 1 inch per hour.

Peak snowfall: The most intense snowfall is expected Friday morning and Saturday morning.

Winds: The strongest winds – between 25 to 45 mph – are expected Friday morning through Saturday.

What else to expect: Snow will mix with rain near Lake Michigan and limit snow accumulations after mid-Friday morning.

Des Moines, Iowa

Alerts: A winter storm warning is in effect until 10 a.m. CT Friday. Then, as winds intensify, a blizzard warning will be in effect from 10 a.m. CT Friday to 6 a.m. CT Saturday. After that, a wind chill watch will be in effect from Saturday evening through Tuesday morning.

Snowfall: During the winter storm warning, 6 to 11 inches of snow is expected to accumulate. During the blizzard warning, when heavy snow combines with ferocious winds, life-threatening conditions are expected.

Peak snowfall: The heaviest snow is forecast between 1 a.m. to 6 a.m. CT Friday.

Winds: The strongest winds – between 30 to 45 mph – are expected Friday morning through Saturday.

Wind chill: Dangerously cold wind will occur with values as low as 30 to 45 below zero. The dangerously cold wind chills could cause frostbite on exposed skin in as little as 10 minutes.

Grand Rapids, Michigan

Alert: A winter storm warning will be in effect from 10 a.m. ET Friday to 7 p.m. ET Saturday.

Snowfall: Between 8 to 14 inches of snow is forecast.

Peak snowfall: The heaviest snowfall is expected from 1 to 6 p.m. ET Friday.

Winds: Wind gusts could reach 50 mph. Winds topping 40 mph are expected between noon and 7 p.m. ET Friday and again between 9 a.m. and 6 p.m. ET Saturday.

Milwaukee, Wisconsin

Alert: A winter storm warning is in effect from 6 a.m. CT Friday to noon CT Saturday.

Snowfall: Expected snow accumulations include 3 to 7 inches along the lakeshore to 6 to 11 inches farther inland.

Peak snowfall: The heaviest snowfall is forecast between 6 a.m. to noon CT Friday

Winds: Strong winds exceeding 30 mph – sometimes gusting up to 45 mph – are expected from Friday morning through Saturday.

Minneapolis

Alert: A winter weather advisory is in effect from 6 a.m. CT Friday to 6 a.m. CT Saturday.

Snowfall: Total snow accumulations could reach 4 to 7 inches.

Peak snowfall: The heaviest snowfall is expected between noon and 10 p.m. CT Friday.

Winds: Fierce winds of up to 35 mph are expected Friday afternoon through Saturday.

New York City

Alert: A coastal flood advisory is in effect for 7 a.m. to 2 p.m. ET Saturday.

Flood risk: 1 to locally 2 feet of inundation above ground level expected in vulnerable areas near the waterfront and shoreline.

“Runoff coinciding with the Saturday morning high tide will exacerbate street and property flooding issues along tidal portions of the Hackensack and Passaic Rivers in Bergen, Essex and Hudson Counties,” warns the weather service in New York.

Philadelphia

Alert: A coastal flood warning is in effect from midnight Friday night to 7 p.m. Saturday.

Flood risk: 1 to 2 feet of inundation above ground level is expected in low-lying areas near shorelines and tidal waterways.

“At this level, widespread roadway flooding occurs along tidal waterways,” the weather service office in Philadelphia said. “Some roads become impassable. Minor damage to vulnerable structures may begin to occur.”

Boston

Alert: A coastal flood watch is in effect for Saturday morning and afternoon.

Flood risk: Up to 1 foot of flooding is possible.

Portland and Eastport, Maine

Flood risk: Water levels on Maine’s coast are forecast to hit historic highs on Saturday, threatening to inflict more damage on coastal communities still reeling from a storm that sent water surging onshore earlier this week.

Water levels at gauges from Portland to Eastport were forecast to top Wednesday’s levels that were swollen from the last storm, according to data from the National Oceanic and Atmospheric Administration. The water level reached 15.49 feet in Bar Harbor Wednesday morning and is forecast to top 17 feet by noon Saturday. In Portland, the water is projected to top 14 feet Saturday morning, more than the record-high 13.84 feet set Wednesday morning.

State of emergency: Maine’s governor issued a state of civil emergency Thursday for all eight of the state’s coastal counties after the destructive storm surge this week.

“Significant rain, wind, and flooding have once again ravaged our state – this time our small communities up and down the coast,” Gov. Janet Mills said. “The damage we are seeing is devastating, from working waterfronts, to small businesses, to public roadways and more.”

This is a developing story and will be updated.

CNN’s Taylor Ward, Mary Gilbert, Eric Zerkel and Joe Sutton contributed to this report.

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