Environment Canada has issued rainfall and wind warnings for eastern Vancouver Island throughout Thursday.
About 60 millimetres of rain is expected to fall in inland sections from Courtenay to Campbell River, and about 40 mm along the coast.
Strong southeast winds of 50 kilometres per hour gusting up to 70 km/h during the rain event is expected to cause rough seas.
The federal agency said the significant rainfall is due to a slow-moving Pacific frontal system that will cover the region most of the day and eventually clear around midnight.
Environment Canada cautioned that flooding is possible in some low-lying areas.
