Dropping temperatures and increasing winds threaten to make matters worse for Hamilton residents already reeling from this weekend’s ice storm.

Tens of thousands of households and businesses were without power on Sunday after the city’s hydro infrastructure took a beating from tree branches that snapped under the pressure of accumulated ice.

And though the freezing drizzle is set to pass over the region late in the day, cool temperatures on Monday and Tuesday raise the spectre of more falling ice and further power outages.

Temperatures in Hamilton may edge up slightly about the freezing mark on Sunday afternoon or into the evening, said Marie-Eve Giguere, a meteorologist with Environment Canada.

However, the slight warming period won’t relieve the stress on weighed-down trees and power lines.

“We don’t expect the ice to melt at all," Giguere said.

Environment Canada expects the Greater Toronto and Hamilton Area to experience lows around -5 C on Sunday night. Temperatures are set to remain below the freezing mark on Monday, and dip down as low as -12 C to -14 C between Monday and Tuesday.

Increasing winds, Giguere said, “is definitely a factor that complicates the situation.”

The combination of the wind with the accumulation of ice on frozen branches and other surfaces “may cause more power outages,” she said.

She warned people not to walk under frozen tree canopies — falling branches can cause serious, even fatal, injuries — and advised residents to check on friends, neighbours and family members who might be without electricity.

Saturday night's ice storm, which continued into Sunday, brought fallen tree branches and downed power lines across the city.

As many as 30,000 households and business were without hydro service on Sunday afternoon, said Horizon Utilities.

The affected customers were mostly concentrated in the Stoney Creek, Ancaster, Dundas and Flamborough areas.

The company had said it expected normal service to resume by 11:30 a.m. But later in the day, Horizon said full restoration may not occur until Christmas Day.

Hydro One, which serves thousands of homes and businesses in the city's rural and suburban area, said on Sunday afternoon that 18,000 of its Hamilton customers — primarily those in Flamborough, Waterdown, Mt. Hope and Binbrook — were without electricity, up from 16,000 earlier in the day.

Because of tree branches falling on hydro infrastructure, new outages popped up as crews worked to fix existing ones, said company spokesperson Marylena Stea.

She said she wasn’t able to give a firm estimate on when normal service would resume.

"We are hoping to have the bulk of people restored today," Stea said. "There will be people without who will go without power overnight.