Many parents — and no doubt many students — across the city were unimpressed by the Ottawa Student Transportation Authority's call to keep buses running this morning despite heavy snow.

Conditions were so bad that Environment Canada issued a winter weather travel advisory for the city, warning of poor visibility and snow-covered roads.

Parents, including Nepean-Carleton MPP Lisa MacLeod, took to Twitter and Facebook to vent their frustration.

It's hazardous out there. <a href="https://twitter.com/OttSchoolBus">@OttSchoolBus</a> needs an examination. Hard to deal with on bus routes & questionable decision making on snow days. <a href="https://t.co/CJH6C3NQuu">https://t.co/CJH6C3NQuu</a> —@MacLeodLisa

As MPP I deal with <a href="https://twitter.com/OttSchoolBus">@OttSchoolBus</a> a lot. No accountability, many complaints. And it snowed all night. No consistency in their calls. <a href="https://t.co/9VnIiPFC5C">https://t.co/9VnIiPFC5C</a> —@MacLeodLisa

<a href="https://twitter.com/MacLeodLisa">@MacLeodLisa</a> my class is empty right now —@RebeccaRuns

Vicky Kyriaco, general manager of the Ottawa Student Transportation Authority (OSTA), said cancellation decisions have to be made by 5:30 a.m. based on the 4 a.m. weather report and the city's plans for snow clearance.

'"At the end of the day, it's up to parents to decide how they get their kids to school. We have a service that we deliver under certain conditions — we can explain how we deliver that service, but if parents don't agree with it, it's up to them whether they want to use it or not," she said.

"We get complaints no matter what we do. It's amazing how many people can be happy or mad all at the same time."

Kyriaco said it has been challenging for OSTA to make these decisions this winter because of the mild temperatures and heavy precipitation the city has seen.

The variation between a few degrees could mean the difference between a wet surface and a "skating rink," or a lot of snow and none at all, she said.