Later Monday, Hochul spoke with President Biden, who offered "the full force of the federal government" to support New York state and said he and First Lady Jill Biden were praying for those who lost loved ones in the storm, according to a White House statement.
    The president also approved an emergency declaration for New York, authorizing the Federal Emergency Management Agency to assist with recovery efforts.
    "Our focus has been on life safety, working in teams, plowing to get to motorists who are stranded in vehicles, plowing and opening up streets to get to people with emergency medical situations," Buffalo Mayor Byron Brown told CBS News in an interview Monday afternoon. "And then also working with our power company, National Grid, to get them to needed locations to restore power."
    "This is probably one of the harshest winter storms this city has seen in over 50 years," he added.
    New Jersey Gov. Phil Murphy said in a statement that he was "deploying New Jersey Task Force One to assist New York with rescue efforts after extreme winter weather impacted the state this weekend, because that's what neighbors do."
    However, temperatures "are expected to moderate across the Midwest and the East over the next few days ahead of this system," the National Weather Service said in its latest advisory early on Tuesday, though it warned that "locally hazardous travel conditions" would persist.
    CBS Buffalo affiliate WIVB-TV said conditions were extremely cold overnight Tuesday and many roads were still impassible. "Do not try to venture out around Buffalo as getting stuck can quickly become a life threatening situation with temperatures mostly in the teens overnight," the station warned.
    But forecasters said the outlook would finally start to improve. "Starting Tuesday night, we will see the snow fade out and temperatures will begin to warm up, even overnight into Wednesday. The remainder of the week is expected to remain above freezing, which will encourage melting," WBIV reported.
    "Currently, no widespread flooding is expected as creeks and streams have room in their banks despite the nearly 2-6 inches worth of water stored in the snowpack. Thankfully, this is not all expected to melt at once."
    National Guard members and other teams rescued hundreds of people from snow-covered cars and homes without electricity, but authorities said more people remained trapped.
    Erie County Sheriff John Garcia called the storm "the worst" he has ever seen, with periods of zero visibility and authorities unable to respond to emergency calls. 
    "It was gut-wrenching when you're getting calls where families are with their kids and they're saying they're freezing," he told CNN.
Hochul, a native of Buffalo, said she was stunned by what she saw during a reconnaissance tour of the city. 
    "It is (like) going to a war zone, and the vehicles along the sides of the roads are shocking," Hochul said, describing eight-foot drifts against homes as well as snowplows and rescue vehicles "buried" in snow.
    The extreme weather sent temperatures to below freezing in all 48 contiguous U.S. states over the weekend, including in Texas communities along the Mexico border where some newly arriving migrants have struggled to find shelter.
    Officials in Jackson, Mississippi, announced on Christmas Day that residents must boil their drinking water due to water lines bursting in the frigid temperatures. That order remained in place Tuesday as crews continued to try to find the source of the leaks.
    "We know that many area are without water and pressure. We know that for some, this problem has been consistent for days," city officials said on a website tracking the community's recurrent water system problems.
    Nationwide, power outages at one point on Saturday left nearly 1.7 million customers without electricity in the biting cold, according to the tracking site PowerOutage.us. That number has dropped substantially, with some 12,000 homes and businesses still in the dark in Maine and New York state as of 6:15 a.m. ET Tuesday.
    Due to frozen electric substations, some Erie County residents weren't expected to regain power until later Tuesday, with one substation reportedly buried under 18 feet of snow, a senior county official said. 
    Buffalo's international airport was to be closed until Tuesday and a driving ban remained in effect for the Buffalo area, though Poloncarz lifted the ban for the rest of the county Tuesday, leaving an advisory warning in place.
    Road ice and whiteout conditions also led to the temporary closure of some of the nation's busiest transport routes, including part of the cross-country Interstate 70.