Vincent Avendano inspects the undercarriage of a car Tuesday at Mr. Tire Auto Service Center in Arlington. The car developed a rattling noise after hitting several potholes. (Dayna Smith/The Washington Post)

About three weeks ago, Wendy Simonson’s midnight blue Jeep careened into a pothole as she exited the George Washington Memorial Parkway in Virginia. She heard a noise near the right front wheel well.

“It sounded like a pebble,” she said. “But then it became a rattling sound, and I knew I had to do something.”

So at 6:45 a.m. Tuesday, Simonson, a 53-year-old State Department construction engineer, was at the door of a Mr. Tire Auto Service Center in Arlington County, part of a parade of customers the shop has seen recently.

After a harsh winter of extreme cold followed by rapid warming and then a return to plunging temperatures, the Washington area is enduring “a pandemic of potholes,” said John B. Townsend II, a spokesman for AAA Mid-Atlantic.

In the District and its suburbs, repair crews have patched many thousands more potholes in the first four months of 2014 than they did in the same period last year, according to transportation officials. And throughout the winter and into the spring, those gaping, jagged holes have been wreaking havoc on tires and wheels.

“You see a lot of bent rims,” said George King, a manager of the Mr. Tire at 5200 Lee Hwy., one of several Washington area tire shops that reported an increase in pothole-related repair business in recent months.

“People are coming in all the time, and you usually don’t have so many people with potholes like this,” King said. “You see the sidewalls of the tires are broken out from hitting the pothole on the inside of the tire — it cuts it where you can’t see it. And alignment problems. Because it rattles the car, the tie rods move, and so you need to realign the car.”

This wasn’t Simonson’s first run-in with a pothole. The Arlington resident said she has hit at least 10 in the past several months. In January, she hit three in one night in the District on her way home from a movie and broke her Jeep’s transmission line.

“You don’t think they’re going to do you in until you see transmission fluid on your garage floor,” said Simonson, who has spent $1,400 on repairs. “It’s a nightmare navigating the streets.”

Every winter brings potholes. Moisture seeps into the pavement, then freezes and expands when temperatures drop. Then the moisture thaws, then freezes again in the next cold snap, weakening the pavement as traffic continues to rumble over it.

Eventually, the concrete crumbles.

“This whole winter was crazy — just all that cold and those very, very wide temperature variations,” said Charles Gischlar, a spokesman for the Maryland Highway Administration. In a typical fiscal year, July to June, Maryland spends about $2.5 million filling potholes, he said. This year, that figure already has been reached.

At the end of March, Gischlar said, workers were repairing 50 to 80 potholes on each fair-weather day in Montgomery and Prince George’s counties, “and there were many days when the total was far more than that, which is pretty bad.”

“Probably the worst pothole season ever,” said Joan Morris, a spokeswoman for the Virginia Department of Transportation. In Fairfax, Arlington, Prince William and Loudoun counties, “the last figure I heard was 5,000 potholes. But it’s well over that by now.”

In the District, where workers fixed fewer than 10,000 potholes during and after the relatively mild winter of 2012-13, this year’s pothole-repair count is at 35,000 and increasing, said Reggie Sanders, a D.C. Department of Transportation spokesman.

“What happened was, all winter, we fixed them,” he said. “Then inevitably the cold weather would return, and then the temperature would go back up, and what we filled the holes with would come right back out. Over and over again.”

One Falls Church tow-truck driver said cold weather isn’t the only cause of the problems.

“The roads are ridiculous. They are destroyed this year,” said Nathan Malashevich, who said he has been towing pothole-damaged vehicles several times a week. “There’s a lot of chemicals they put down on the roads and there was a lot of plowing. The trucks tear up everything.”

Malashevich has seen it all. Sometimes, hitting a pothole causes a vehicle’s air bags to deploy. Other times, there’s a ruined tire. He said he can usually tell when a vehicle has been damaged by a pothole: Typically, the car is stopped about 15 feet from where it hit the jagged pavement. “The holes are so deep,” he said.

Townsend said AAA members with flat tires have been calling for roadside help in greater numbers this year than last, which he attributes largely to potholes. In the group’s Mid-Atlantic region, from New Jersey to Richmond, AAA answered 121,076 flat-tire calls from Jan. 1 to April 27, compared with 97,096 in the same period last year.

Locally, Townsend said, AAA responded to 5,077 calls in the District (up from 4,264 during the first four months of last year), 28,172 in Maryland (up from 24,523), and 17,050 from Northern Virginia to Richmond (up from 15,818).

“I’m seeing 12 to 15 damaged tires a day,” said Kenneth West, a supervisor in the tire department at Costco in Northeast Washington. He said some of the damage is caused by normal road debris, especially nails, but there also has been an increase in business related to potholes. “And that’s just warranty work. A [Costco] member buys a tire from us, they go out and hit a pothole, and they’re back in here for work.

“New tires? Tires sold because of that problem? It’s been an increase lately, over the last two months. We’ll see probably 30, 40 tires sold through the week.”

At Action Al’s Tires, in the 2500 block of Bladensburg Road NE, David Stestegren said customers of the shop seem amazed at the damage a pothole can do.

“They tell me, ‘Dave, I didn’t even see it! I just hit it!’ And I know, I know. If it’s rainy, the pothole’s full of water. At night, you can’t see it. Even if it’s daytime, you come right up on it before you realize it’s there. And you don’t know whether to hit it or try to avoid it, which might cause an accident. I tell them, ‘I know, I know.’ It’s been real bad this year.”

Being a tire man, Stestegren has invested in protection.

“What saves me is, I have a truck with these Goodyear reinforced Kevlar SilentArmor tires on there,” he said. “That helps absorb the impact. But most of these cars that sit low to the ground and have these alloy wheels, and they have tires with no sidewall protection, this is what’s going to happen. I see it all the time.”

Bob Stine, 59, a computer programmer who commutes from Arlington to Bethesda, said the problem is nothing new.

When it comes to hitting a pothole, “who hasn’t?” Stine said. “You can’t avoid them.”

Simonson, who plans to do more cycling to avoid potholes, is having her bicycle repaired, too. She even mused about biking to Mr. Tire to pick up her Jeep.

“I realized my Jeep is not invincible,” she said, calling her experiences with potholes a wake-up call. “I have to be more gentle with it.”