PROVIDENCE — Thirty public school buses were late again yesterday morning, leaving dozens of children waiting from 30 to 60 minutes in the frigid weather.

Once again, icy roads were blamed for the delays, which affected elementary and middle school students. According to school spokeswoman Christina O’Reilly, the First Student buses had trouble chugging up the hill that leads from the bus yard at 3 Ricom Way. Officials said the buses left between 5:55 and 6:15 a.m., and once they cleared the hill, had to navigate roads clogged with snow and ice from two storms, which dumped more than six inches of snow on the region in four days.

Providence wasn’t the only city having busing nightmares. In Boston, more than 680 students were stranded yesterday after 70 bus drivers skipped work. The no-shows called in sick or used personal days.

After consulting with the city’s Department of Public Works, Providence Supt. Donnie Evans decided yesterday at 5:30 a.m. to open the schools on time. Around 7:30 a.m., word began trickling in that the buses were having trouble making it up the hill.

“We had information that they were running a bit late,” O’Reilly said yesterday, “but we didn’t know until 8:45 a.m. that the delays were that bad.” Evans immediately asked the DPW to re-treat the roads around the bus depot.

Parents, however, were not notified of the delays until 9 a.m., when the School Department sent out a computerized phone message to all elementary and middle school families. High school students were not affected because they take RIPTA buses to school.

Parents, already fuming from the mass bus stranding during Thursday’s storm, had little patience for yesterday morning’s delays. In an automated phone message sent by the School Department, parents were told to contact First Student with any questions about the latest busing delays.

“Communication seems to be an ongoing problem,” said Liz Colon in an e-mail to The Journal. “When will they pick up the phone and call each other? They need to get it together and quickly. Come on, this is New England. What else do you expect in winter. I expect the city and the School Department to do much, much more.”

Lauren S. Zurier, an East side parent, expressed similar frustration:

“So if the hills next to the bus yard were too icy, why wasn’t First Student on the phone to the School Department right away” she said in an e-mail. “It’s not like the buses were en route and couldn’t be contacted. They were right out the window of the First Student office!”

At the height of Thursday’s storm, 60 school buses were stuck in massive traffic jams that tied up every major roadway leading in and out of Providence. While police officers threaded traffic to ferry the children home, parents waited anxiously for word of their children’s whereabouts. In some cases, youngsters didn’t arrive home until 10:30 p.m. Meanwhile, the elementary schools became makeshift shelters, providing children with snacks and games until the buses arrived.

Yesterday, several parents said they drove their children to school after waiting 20 minutes or more for the bus. What about the children whose parents had already left for work, they wondered. What happened to the students whose families don’t have cars?

“A message was left on our answering machine at 9:10 a.m.,” said Pam Dowland. “That’s great, isn’t it? After standing in the cold. Our street is still waiting to be cleared. Wake up, Providence. You’re being taken advantage of by these snowplow drivers.”

Once First Student was aware of the problem, the company sent additional buses to pick up the waiting students. O’Reilly said that everyone was in school by 10 a.m. One possible victim of the bad weather was school attendance: 17 percent of the city’s 25,000 students didn’t turn up for class yesterday, almost twice the usual rate.

Meanwhile, Evans met yesterday with his senior administrators to begin figuring out what went wrong during last week’s storm: “We’re engaged in extensive discussions about what we did right, what we did wrong and what we can do better,” O’Reilly said. “We’re gathering data internally that we can provide to the mayor.”

Mayor David N. Cicilline announced on Friday that he is launching an investigation into Thursday’s fiasco and said he expects a full report by the beginning of next week.

lborg@projo.com