Like strange creatures in a bad horror movie, they're popping up all over, growing bigger, bigger.
But these pests aren't giant cockroaches from outer space they're all too familiar, especially to drivers whose cars' shock absorbers are worn down.
The number of potholes in the city is "in the hundreds, maybe close to 1,000," said Tom Orzulak, maintenance manager for the city's street division. "All I can say is there's a lot."
Nine workers in three city crews have been repairing potholes all day, each day, since winter precipitation stopped earlier this week, Orzulak said. In normal weather, the city usually maintains one crew for pothole repairs, he said.
"WE HAVE at least a good week of work on the major roads for all three crews," he said.
The crews, Orzulak said, are concentrating repairs on North Second Street, Haskell Avenue, Massachusetts between 11th and 23rd streets, and Kasold between Sixth and 31st streets.
"There's a lot of other holes on residential streets, but they're not as critical as the streets we're working on now," he said.
Pothole repairs in residential areas will begin after the main streets are completed.
Crews are repairing most areas of damaged road with temporary, cold-material fillers, Orzulak said. Permanent repairs are made in the summer, when hot materials can be used to fill the holes.
"We've just started" contending with an annual scourge of potholes in the area, said Tom Mulinazzi, associate dean of engineering at Kansas University and a specialist in road conditions.
Mulinazzi said a large amount of snow or ice such as was dumped recently on Lawrence does not directly cause potholes. Instead, potholes are formed by a combination of moisture and temperature fluctuations.
WATER SEEPS under the road surface, freezes and then thaws. When water freezes, it expands and causes cracks in the road, Mulinazzi said. As cars and trucks pass over cracks, they may knock out small pieces of pavement, causing the start of a pothole. The pothole grows bigger as more vehicles knock out more of the road surface.
Road conditions generally will remain good as long as the area doesn't go through several freeze-thaw cycles, he said.
"If it stays below freezing for the next two months, we'll be OK," he said.
The number of potholes is almost directly related to the number of times the temperature fluctuates above and below the freezing mark, he said.
"WHEN YOU have a lot of freezing and thawing, the worse it will be," Mulinazzi said.
Water, he said, can seep under roads in two ways: through small cracks in the surface of the pavement and from underneath the road.
"As you remember, we had a lot of rain before this latest cold period," he said. "Now you're seeing what happens when some of that water freezes and is starting to thaw out."
Orzulak said frequent snow plowing has put additional stress on roads this year.
"Anytime you're doing a lot of plowing you're going to have more potholes," he said. "Any little weak piece of pavement you have, the snow plow is going to take it out."
MULINAZZI says the best way for engineers to prevent potholes is to design adequate water drainage around roads.
"I have a saying I always tell my students, `If you can drain it, you can maintain it.' "
But that's not always easy, he said.
"This happens every year, it's natural," he said. "People just complain about potholes whether there's 10 or 100, especially if they're on their street."
Anyone noticing an especially severe pothole may call the city street department, which maintains a pothole repair list. But Orzulak said the city has received fewer than 20 calls from residents about potholes.
"We haven't had as many citizen complaints as I thought we'd have," he said.