3 Oct 12 @ 2045hrsWitnessed from my houseEvent One - Pulsating light above low cloud cover illuminating the clouds west of Petawawa, ON though out the western sky. This light moved throughout the sky lighting up area approx 10 miles moving from one area of the sky and back again, then stationary, then moving again. This was above the cloud cover and extremely bright.Event Two - Approx 5 minutes later. White appears from nothing below cloud cover from same direction (West of Petawawa). Direct line of sight from house, no obstructions. Visible for approx 5 seconds, then incredible flash of light across the whole sky 360 degrees from object. When flash went out, object was gone.My wife witnessed event one. Petawawa is an interesting place as it is home to a very large military base since 1905 complete with training area and the Claulk River Nuclear Facility to the north of the base. This event did not take place above the base or nuclear facility.