A Cowichan Valley resident takes a trip through town in his canoe after two local rivers overflowed their banks on Friday. (CBC)A flood watch has been issued for large parts of Vancouver Island as officials warn more than 100 millimetres are forecast to fall over the next 24 hours.

The storm is expected to blow in Tuesday afternoon, causing a significant risk of flooding on the east, west and central parts of the island on Wednesday and into Thursday, including the Duncan and North Cowichan areas on the southeast side of the island that were flooded on Friday.

The west coast of the island is expected to get the heaviest rainfall with totals of up to 100 millimetres, while the east coast is expected to receive moderate rainfall of roughly 30 to 60 millimetres.

No evacuation orders or alerts have been issued, but warmer temperatures brought on by the storm front are expected to raise the freezing level up to 2,500 metres, meaning a large amount of snow that has fallen in the mountains in recent weeks is likely to melt into the rising rivers.

Officials also warn Vancouver Island has already received very large amounts rain over the past two weeks, and that lake levels are very high, soils are saturated and runoff rates are expected to be high.

Rivers across west and central Vancouver Island are expected to start peaking by Wednesday morning, while rivers on the east coast are expected to peak Wednesday afternoon or evening.

Officials are hopeful that the peak river flow in the North Cowichan area will coincide with low tides overnight Wednesday.

More than 300 homes in the area were evacuated on Friday after two the Cowichan and Koksilah rivers overflowed their dykes. At least 15 families have yet to be able to return to their homes.