School is closed today for nearly 50,000 elementary students at the Ottawa Carleton District School Board, as teachers begin a one-day strike.

Pickets are going up at 117 schools across the city.  The job action affects nearly 3,000 full time teachers and 2,400 occasional teachers. The Board has decided to close all elementary schools for today only.

Peter Giuliani says about 3300 teachers are picketing at 70 sites until about 2:15. Giuliani says that's nearly 99% compliance which, he says, isn't surprising given the 97% strike vote.

When asked whether teachers would walk out again before Christmas, Giuliani says more action is a possibility if the government comes down hard regarding the December 31st deadline.

One school with striking teachers will remain open today; Longfields Davidson Heights in Barrhaven is the only Ottawa school that serves students from Grades 7 to 12. High school teachers briefly joined their elementary counterparts on the picket lines before going in to work.   Some teachers had their children join them in the picketing.

The strike has forced parents to make alternative arrangements for their children.

All striking elementary teachers with the Ottawa Carleton District School Board are to attend a post-strike rally at the Nepean Sportsplex at 2:30 this afternoon.

Strike action is also happening today at Prince Edward Hastings in Eastern Ontario and Lakehead in Thunder Bay.  Teachers at the Renfrew County Board will stage their action tomorrow.

CTV's Joanne Schnurr has been assigned to this story.  Follow her on Twitter for regular updates then watch her stories today at noon and 6:00.