USD/CAD recently faced resistance near March high of 1.3860/1.3900 which is also the upper limit of a multi-month channel. This test has resulted in a quick decline. 

A short-term down move towards 1.3700, the 23.6% retracement from July is expected. 

Lower band of the channel near 1.3570 is likely to be an important support near term. Only if this gets violated would there be risk of a deeper down move.