At a news conference at City Hall on Thursday afternoon, city leaders addressed what quickly has become Duluth's pothole problem.

"We've gone straight from plowing to potholes," said Noah Schuchman, Duluth's chief administrative officer.

Public Works and Utilities Director Jim Benning said crews were out clearing about 11,000 catch basins as well as steaming culverts. He called this year "exceptionally bad" for potholes in Duluth. He couldn't pinpoint a reason why the roads are in such bad shape this year, but said it might be because of the heavy snow that fell in February, which kept plows on the streets longer.

Benning said the city has identified several particular areas of concern and that crews would be out patching those streets as soon as possible. They include South Lake Avenue on Park Point — from just across the Aerial Lift Bridge through the S-curve at 12th Street — and Superior Street through much of Congdon Park and Lakeside, with a particularly bad area near 54th Avenue East.

Portions of Woodland Avenue will also be patched, but the city is focusing less on that area because a reconstruction project on Woodland north of Arrowhead Road is planned for this summer, Benning said.

As a temporary fix, crews are using a "cold mix" of asphalt, which stays more pliable in cold weather, Benning said. The city is waiting for plants that make a "hot mix" to open so that the city can begin more permanent patch work, probably by May, he said.

Benning said that in the meantime residents can help by being careful on city streets and by helping to clear catch basins and other drainage areas.

Duluth Mayor Emily Larson said the city is seeing a "difficult transition of seasons" but noted that many city systems are working well amid challenging conditions.

Larson has been in St. Paul in recent weeks, trying to garner support for a new, half-percent increase in the city's sales tax, which 77 percent of Duluth voters approved in a November 2017 referendum.

The new tax would help pay for street improvements, bringing in an extra $7 million per year. However, the new tax still needs approval from the Minnesota Legislature.

Rain overnight raises flooding concerns

With the ground still frozen, widespread rain across the Northland late Wednesday into Thursday has residents and local officials on watch for flooding.

Rainfall totals generally ranged from half an inch to 1.5 inches across the region.

The entire region remained under a flood watch through Thursday evening, according to the National Weather Service, except for Koochiching County, which sits on the rain-snow line and was under a winter weather advisory. Between 2 and 4 inches of snow were expected to fall in the northwestern part of the county on Thursday.

With temperatures above freezing Thursday, the rain was expected to combine with melting snow, leading to street flooding, the Weather Service reported. Basement flooding and ice dam backups on roofs were also a concern.

The Weather Service also says that heavy, rain-soaked snow on rooftops could put them in danger of collapsing, particularly on barns and outbuildings.

The city is seeing areas of localized flooding in lower-lying neighborhoods including Fond du Lac, Gary-New Duluth and Lakeside, according to Chris Kleist, Duluth public works utility operations supervisor. Park Point also is a challenge, he said, because storm sewers are either at or below lake levels, so water is draining, but slowly.

As of 11 a.m. Thursday, the National Weather Service office near Duluth International Airport had seen 0.63 inches of rain, while other parts of Duluth received three-quarters of an inch or more.

Historically, the snow-to-rain ratio in Duluth has been about 14-to-1 to 15-to-1, according to meteorologist Kevin Huyck with the Weather Service in Duluth. So, with those values, Duluth's official rain tally would translate to between 8.8 and 9.5 inches of snow if conditions were colder. However, Huyck said, those numbers make a number of assumptions and are not ironclad.

A weather station near Beaver Bay had the highest rainfall amount Thursday morning, with 1.24 inches. Rainfall appeared to be heavier generally north and west of the Twin Ports, while lesser amounts were reported farther south and east.

Duluth public schools Superintendent Bill Gronseth said buses had trouble accessing a handful of rural, ice-covered gravel roads Thursday morning but that there were no major problems. In the event that a bus can't reach part of its route, Gronseth said that parents are called and informed of the situation.

The rain didn't cause major issues at the Western Lake Superior Sanitary District's wastewater treatment plant in Duluth, said Marianne Bohren, WLSSD's executive director. The plant treated about 90 million gallons of wastewater on Wednesday, up from an average of about 40 million gallons. Overflow issues typically don't arise until that level reaches about 150 million gallons, Bohren said.