jbeiber082811_01_X17WM230.jpgBruce and Diane Dale, Justin Bieber's grandparents, were involved in a car accident Tuesday afternoon.

The couple were driving in the snow near Stratford, Ontario when they lost control ... rolling the car and ultimately smashing into a tree, according to Ontario police.

Bieber's mom, Pattie Mallette, Tweeted on Tuesday:

    "My parents got into a car accident today. They flipped into a ditch & totaled the car but thank God they are alive! My dad has broken ribs. Plz pray 4 him 4 quick healing! Count your blessings & forgive ur parents always. U never know what tomorrow holds!!!"

Both are expected to make a full recovery. Biebs has yet to issue a comment on the incident.