BUFFALO, N.Y. -- First came the big storm, then the big dig. Now comes the big melt.

Residents of flood-prone areas around Buffalo should move valuables up from the basement, pack a bag and prepare for the possibility of evacuation as up to 7 feet of melting snow posed the threat of flooding, Gov. Andrew Cuomo warned Sunday.

"Err on the side of caution," Cuomo said at a news conference in Cheektowaga, New York. "You prepare for the worst and hope for the best, and that's what we're doing."

Across the Buffalo region -- where temperatures were expected to approach 60 degrees today -- people took that advice to heart.

In Hamburg, Pete Yeskoot bought a portable generator to make sure his sump pump will keep working once the roughly 80 inches of snow that fell on his property melts. Possessions are up on blocks in the basement and he has food for several days.

"Behind us is an 18-mile creek so everything in the village will come through us at some point, so we have to get ready for the possibility of flooding," he said. "And given all this snow, we have to expect that this is real."

Rain fell Sunday, with temperatures rising to 50. It was expected to be even warmer today, accompanied by more rain and rising winds, leading to the threat of toppled trees and power outages.

National Guard members spent Sunday clearing storm drains and culverts to facilitate runoff, and shoveling snow off roofs.

The National Weather Service said core samples of the deep snowpack showed it contained as much as 6 inches of water. Forecasters said some stretches of road in urban areas might become submerged under several feet of water if storm drains remained clogged.

The melt could first cause basements to fill up and roads to flood, but another concern was creeks overflowing. In West Seneca, there was already a sewer pump stationed near Michelle Pikula's house along the Buffalo Creek.

"Hopefully the rain won't be here until later and this will be a slow thaw, but flooding is our major, major concern here," she said.

Cuomo said evacuation plans and emergency shelters were being readied in case of flooding Sunday night and Monday. As a backup to Red Cross shelters, Cuomo said the state would have shelters at community colleges and state university campuses.

The state Thruway, which had been closed for 132 miles at the height of the lake-effect storm last week, was entirely open Sunday. All driving bans were lifted except in Lackawanna, where snow-removal crews worked to open up streets that had become parking lots with hundreds of abandoned, buried vehicles.

Most snow-affected school districts remained closed Monday, and at least four called off classes for the entire Thanksgiving week.