ATLANTA — Brutal, record-breaking cold descended on the East and South, sending the mercury plummeting Tuesday into the single digits and teens from Boston, New York and Washington to Atlanta, Nashville and Birmingham — places where many people have almost no idea how to deal with freezing weather.

The morning weather map for the eastern half of the U.S. looked like an algebra worksheet — lots of small, negative numbers. In fact, the Midwest and the East were colder than much of Antarctica.

The deep freeze started in the Midwest over the weekend and spread east, blanketing about half of the country. In New York City, the high was expected to be 10; in Boston, around 18.

Birmingham, Ala., dipped to a low of 7. In Atlanta, which saw a record low of 6 degrees, fountains were frozen over, pipes burst and cars wouldn’t start.

“This is severely cold for these parts,” said Brian Lynn, a National Weather Service meteorologist in Peachtree City, Ga. “Single digits are a rare event.”

Farther south in Pensacola, Fla., a Gulf Coast city better known for its white sand beaches than frost, streets normally filled with joggers, bikers and people walking dogs were deserted early Tuesday as temperatures remained in the teens after sunrise. Monica Anderson and Tommy Howard jumped up and down and blew on their hands while they waited for a bus, struggling to stay warm.

Anderson said she couldn’t it recall it ever being so cold.

“I’m not used to it. It is best just to stay inside until it gets better,” said Anderson, who had to get out for early morning appointment with her doctor.

A sign on a bank near the bus stop flashed 19 degrees at around 8 a.m. Patches of ice sparkled in parking lots where puddles froze overnight.

Farmers were worried about their crops.

Diane Cordeau of Kai-Kai Farm in Indiantown, Fla., about 90 miles north of Miami, had to pick her squash and tomatoes Monday to beat the freeze but said her leafy vegetables, such as kale, will be sweeter and taste better because of the cold.

“I’m the queen of lettuce around here, so the colder the better,” said Cordeau, whose farm serves high-end restaurants that request specific produce or organic vegetables.

In the East, a blizzard smothered western New York with up to 18 inches of snow and wind gusts of up to 50 mph. As much as 3 feet of snow could fall there by the time the storm eases Wednesday.

Temperatures in parts of West Virginia hit lows not seen for 25 years, while the cold in Virginia broke records that had stood since the late 1950s. The National Weather Service said the mercury bottomed out at 3 degrees before sunrise at Baltimore-Washington Thurgood Marshal International Airport, with a wind chill of minus 16.

Jeffery Oldham Jr., a mechanic at a truck stop on I-70 near Hagerstown, Md., wore a camouflage cap, hunting gloves, double layers of clothing and a heavy parka. He said that he was trying to go inside every 15 minutes to warm up, and that mending a fuel pump took seven or eight minutes.

“Long enough to feel like my face was going to freeze,” Oldham said. “It wouldn’t be too bad out if it wasn’t for the wind.”

Lynn Palmer, of Alexandria, Va., was commuting by bus and train Tuesday to reach her job as an administrative officer at a nonprofit in Washington. She bundled up in layers.

“I could barely walk,” the lifelong Alexandria native said, describing the temperatures as the lowest she had ever experienced.

Forecasters said some 187 million people in all could feel the effects of the “polar vortex” by the time it spread across the country.

PJM Interconnection, which operates the power grid supplying energy to more than 61 million people in the Mid-Atlantic, Midwest and South, asked users to conserve electricity because of the cold, especially in the morning and late afternoon. In South Carolina, a large utility was using 15-minute rolling blackouts to deal with demand.

Meanwhile, recovery was the focus in several Midwestern states. The subzero cold followed inches of snow and high winds that made traveling treacherous and was blamed for numerous deaths in Michigan, Illinois, Indiana and Ohio.

Illinois Gov. Pat Quinn and Indiana Gov. Mike Pence issued disaster declarations, a first step toward seeking federal aid.

At least 15,000 customers in Indiana were without power early Tuesday. Utility crews worked to restore service as temperatures plunged into the negative teens, but officials warned that some customers could be in the cold and dark for days.

“My kids are ready to go home, and I’m ready too,” said Timolyn Johnson-Fitzgerald, of Indianapolis, who faced a second night sleeping on cots at a Red Cross shelter with her three children, ages 11, 15 and 18.

More than 500 Amtrak passengers spent the night on three trains headed for Chicago that were stranded because of blowing and drifting snow in Illinois. Spokesman Marc Magliari said all the passengers, traveling from Los Angeles, San Francisco and Quincy, Ill., would reach Chicago by train or bus later Tuesday.

Warmer weather — at least, near or above freezing — is in the forecast for much of the eastern half of the U.S. Indianapolis should reach 27 degrees on Wednesday, and other cities in the Midwest and in the East could climb above freezing later in the week.

Associated Press writers Steve Karnowski and Amy Forliti in Minneapolis; David Dishneau in Hagerstown, Md.; Brett Zongker in Washington, D.C.; Brett Barrouquere in Louisville, Ky.; Melissa Nelson-Gabriel in Pensacola, Fla.; Suzette Laboy in Indiantown, Fla.; and Kelly P. Kissel in Little Rock, Ark., contributed to this report.