The hoods stopped cars in the middle of the road in the Glencar area and then attacked them with snowballs.
At one stage the teenage terrors managed to push at least two cars into the middle of the road and caused a huge build-up of traffic in the residential area.
One resident, whose car was stopped by the youths, said it appeared the young vandals had been drinking.
“You can understand kids having a bit of fun but this got way out of hand. They were pelting cars with dozens of snowballs when they managed to slow them down.
“There was a lot of older people in cars and it just wasn’t funny. There were a few children crying as well.
“They stopped me and it appeared like some of them had been drinking which is ridiculous considering it was early morning when all this was happening.
“They even managed to push a car into the middle of the road and blocked traffic for ages,” he said.
The man said he telephoned Letterkenny Gardai but was surprised to be told that Gardai could not respond as they were ‘snowed in’.
The gang eventually broke up when a number of army and Garda personnel arrived on the scene.
Today one resident emailed us to say: “I just wanted to thank the army and Garda officers who got rid of these thugs yesterday. We were terrified and their arrival saved the day.”
Elsewhere Gardai said they had received a number of calls of minor disturbances.
The number of people on the roads dropped dramatically over the weekend and, although there were dozens of minor accidents, there were no reports of serious injuries.
However with temperatures dropping to -15 degrees last night, and snow in places, Gardai were again asking people to take care.
Although many schools are again closed this morning, there will be a much greater volume of traffic on the road with people attempting to return to work after the weekend.