VICTORIA -- Keep you umbrellas and raincoats close at hand because Mother Nature will bring Vancouver Island lots of rain to usher in 2020.

Environment Canada issued a rainfall warning for parts of the West Island as a frontal system dumped rainfall totals near 100 millimetres Tuesday. The South Island will not see as much rainfall, but it is going to be wet as we welcome the New Year.

"Today is a wet one and at the end of the week we have another wet pulse to contend with," said Environment Canada meteorologist Armel Castellan. "Having started overnight, somewhere around 15 to 20 millimetres is the best estimate for this particular storm and then we have probably a similar amount coming up for Thursday and Friday."

The rain will taper off later Wednesday but will begin to fall mid-day Thursday and last into Friday. The rain is expected to stop by Friday evening.

"Those first few days are a mixed bag so we will definitely see a little bit of a drying trend before the end of the week gets really wet again," said Castellan. "This is an active stretch and we haven't had too much of it this fall and winter so this is kind is kind of making up for what we have been missing."

Accumulations of rainfall can change very rapidly when you get into the mountains. Areas around the Sooke watershed and the Malahat will see more rainfall than in Greater Victoria. Treacherous driving conditions can be expected on the Malahat, Sutton Pass and the Port Alberni Summit.

"There are many locations on the island where just a few hundred metres makes a big difference in what you are going to encounter driving on those highways," said Castellan.

The western side of Vancouver Island has already experienced very heavy rain that may have caused flooding in low-lying areas. As much as 100 millimetres fell in the past 12 hours with an intensity of 15 millimetres an hour in some areas.

"When we see intensities of rain this strong and lasting for many hours, those are the types of concerns that are certainly on emergency management perspectives on what could and might happen," said Castellan. "It is going to continue to rain most of the day, especially on the outer coast, but generally the whole south coast is affected by this rain."

Residents are advised to watch for possible washouts near rivers, creeks and culverts.