Staff Sgt. Steve Crawford says 30-year-old Susan Mitchell put her children to bed in the family's Burnaby apartment on July 2, but was gone when the youngsters awoke the next morning.
Crawford says the disappearance is out of character and the case is considered "high risk."
No other details have been released.
Police are hoping to talk to anyone who may have seen Mitchell since Tuesday.
She is described as 5' 6" (170 cm) with a medium build and shoulder length blond hair with dark brown roots.
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