With a wind chill, temperatures are expected to drop as low as 15 degrees below zero Fahrenheit (minus 26 degrees Celsius) in large portions of Arkansas, Mississippi, Missouri, Tennessee, Kentucky and Kansas, the National Weather Service predicted.

MEMPHIS, Tenn: Memphis residents were urged to boil water and New Yorkers have been warned that roads could be covered with dangerous black ice this weekend as brutal cold and inclement weather continue to sweep across parts of the U.S.

Bitterly frigid air spilled into the Midwest from Canada on Friday and several states were under advisories as forecasters warned that wind chills dipping to minus 30 degrees Fahrenheit (minus 34 degrees Celsius) could be common through Sunday morning.

Heavier-than-forecast snow fell in New York City, Baltimore and Washington, D.C., on Friday. Storms have walloped the Pacific Northwest, Midwest, Plains, South and Northeast with low temperatures, heavy snow, ice storms, freezing rain and high winds for the past two weeks.

With a wind chill, temperatures are expected to drop as low as 15 degrees below zero Fahrenheit (minus 26 degrees Celsius) in large portions of Arkansas, Mississippi, Missouri, Tennessee, Kentucky and Kansas, the National Weather Service predicted.

The bracing weekend weather follows a series of storms blamed for at least 55 deaths around the country, many of them involving hypothermia or road accidents.

Tennessee recorded 19 deaths alone. They included a 25-year-old man who was found dead on the floor of a mobile home in Lewisburg after a space heater overturned and turned off, said Bob Johnson, chief deputy for the Marshall County Sheriff’s Office.

“There was ice on the walls in there,” Johnson said.

Days of cold broke so many water mains in Memphis, Tennessee, that water pressure fell throughout the city. On Friday, Memphis Light, Gas & Water urged all of its more than 400,000 residents to boil water for drinking or teeth brushing or use bottled supplies.

It wasn’t clear how long the advisory will be in force. While some 50 ruptures were repaired, utility President Doug McGowen warned of new leaks emerging.

A significant drop in blood donations, partly linked to the weather, led Blood Assurance to recommend that more than 70 hospitals in five states halt elective surgeries until Wednesday to allow inventory to be rebuilt by the organization based in Chattanooga, Tennessee.

In West Virginia, advisories and warnings were out Saturday because of continued fierce weather. The weather service said some regions could see up to 4 inches (10 centimeters) of additional snow with winds gusting to 40 mph (64 kph) and wind chill driving down temperatures as low as 20 below zero (minus 29 C).

The West Virginia Legislature left after a brief session Friday because not enough lawmakers could get through snow-covered highways to the Capitol to vote on bills.

In Washington D.C., snow fell softly and the streets around the U.S. Capitol were silent. Schools closed for the second time in a week and the federal government was on a two-hour delay. However, President Joe Biden still welcomed mayors from around the country to the White House for the U.S. Conference of Mayors.

In Buffalo, New York, lake-enhanced snow finally moved out after burying parts of the city and some suburbs in five feet of snow in five days. The Buffalo Bills on Friday renewed a call for snow shovelers, offering $20 an hour for help digging out Highmark Stadium before Sunday’s divisional playoff game against the Kansas City Chiefs.

Michigan City, Indiana, received 17 inches (43 centimeters) of lake-effect snow on Friday. The snow later eased as a low pressure system moved away but the weather service warned that “much colder air wraps in behind it,” and urged drivers to watch out for patches of slick and treacherous black ice.

On the West Coast, Oregon Gov. Tina Kotek on Thursday declared a statewide emergency following deadly ice storms. The weather service reported that temperatures Friday were finally above freezing for most areas and ground snow and ice would slowly begin to melt.

More freezing rain was forecast Saturday in the Columbia River Gorge and the area was expected to remain near or below freezing through at least Sunday night. Trees and power lines already coated with ice could topple if they get more, the National Weather Service warned.

“Stay safe out there over the next several days as our region tries to thaw out,” the weather service said. “Chunks of falling ice will remain a hazard as well.”

Thousands have been without power since last weekend in parts of Oregon’s Willamette Valley because of storm damage. Despite work by repair crews, more than 63,000 customers were without electricity in the state as of Friday night, according to the website poweroutage.us.

The National Weather Service said there could be a thaw next week, when the forecast calls for above-average temperatures across almost the whole country.