Ice skating season has begun in downtown Portland – on the sidewalks, anyway.

A combination of rain and cold nighttime temperatures this week sent Portlanders slip-sliding across brick sidewalks glazed with ice and topped with water. It also sent some unlucky people to local emergency rooms for treatment of sprained ankles and wrenched backs.

“It doesn’t take more than a second for you to end up on your keister,” said Dr. Nathan Mick, medical director of Maine Medical Center’s emergency department.

Conditions were especially extreme late Tuesday and early Wednesday, with sidewalks more slippery than some downtown residents have seen in a long time. Brick sidewalks that become wet and freeze tend to be extra slippery because they are smoother than concrete and asphalt sidewalks, said Eric Labelle, assistant director of Portland Public Services.

The slick bricks caused many to shuffle and slide their way around the city, while others gave up and walked on roads that were wet but nowhere near as icy. Others bought up local supplies of urban ice-trekking gear – studded footwear that can be slipped over or strapped on boots and shoes.

Warming temperatures thawed most downtown areas Wednesday, but the pedestrian-friendly weather may not last. Forecasts call for continuing rain or snow showers through Friday and temperatures falling below freezing Thursday night and Friday night.

Mick said 6 to 10 patients arrived at the emergency room Wednesday after falling on icy steps, driveways or sidewalks. None was seriously injured.

“Any time you get that nice glaze of ice, that’s probably the highest-risk time for falls,” he said.

Herb Adams, a former legislator from Portland and a frequent traverser of the city’s downtown sidewalks, moved slowly across the icy bricks next to Deering Street on Wednesday morning, one L.L. Bean boot sliding forward at a time.

But the conditions were not as bad as Tuesday evening, when he got off the bus near Congress Street and tried to walk downhill toward the Parkside neighborhood. He kept his Bean boots under him, but others were not so fortunate and ended up on the ice-coated bricks.

“People coming up and going down were falling,” Adams said. “If you were near enough, you’d slide over and help them up and hope that you would make it” without falling, too.

Ashley Pandell encountered the same ice-rink conditions at 10 p.m. Tuesday when leaving work on Congress Street.

“I slipped going down this little tiny hill. I didn’t fully fall, but I definitely looked kind of stupid,” she said, mimicking how she waved her arms to keep her balance.

Another woman did fall as she walked to her car, Pandell said, although the woman did not appear to be hurt. “She said ‘Portland should be ashamed of itself because of these sidewalks.’ And I totally agreed.”

City officials say they prioritize clearing sidewalks – especially near schools and in the downtown district. But this week’s weather made it difficult to keep up. On Tuesday night, it was raining even as the temperature began to dip to a low that night of 21 degrees, creating ice with standing water on top.

“When it’s 25 degrees, it’s usually not raining,” said Labelle, the public services assistant director. “Snow is a little bit easier to manage.”

The city maintains about 95 miles of sidewalks, including 14 miles in the downtown district and 81 miles of trails and school walking routes. During and after winter storms, city crews first clear and treat sidewalks in the downtown district and radiating out from schools.

Although the public services department does use a fleet of sidewalk tractors to clear snow and ice, a city ordinance requires that property owners clear the sidewalks in front of their homes and businesses. In some cases involving sidewalk complaints, a city staff member will leave a notice for the property owner as a reminder of their responsibility. In rarer cases when property owners don’t clear their sidewalks, the city can hire a contractor to remove the snow, then charge the homeowner.

The ice on the brick sidewalks outside Reny’s Department store on Congress Street meant brisk business for Yaktrax, Stabilicers and other brands of anti-slip foot gear that can be worn over boots. The traction devices come with metal studs and sell for $16 to $30 a pair. Reny’s has been selling as many as 50 a day, said Scott Witt, a supervisor at the store.

“The amount of times we’ve run out this week has been constant. Fortunately, we got two or three new boxes today,” Witt said Wednesday. “With all that brick out there it is good to have something.”

The bricks seems to hold the cold and freeze more than the asphalt or concrete surfaces, he said.

Mick, the emergency room doctor, said he tends to see more injuries from falls when there is ice or a little snow than when there is deeper snow to cushion the fall. The most common injuries from weather-related falls are sprained ankles and strained backs. It’s never unexpected to see those types of injuries during winter, he said, but he advises people to use common sense when they’re out in slippery conditions.

“If you’re taking extra care driving your car, you should take extra care walking,” he said.

Staff Writers Leslie Bridgers and John Richardson contributed to this report.