Pineapple Express brings more rain and snow to B.C., warm up on the way

Tuesday, February 11, 2014, 8:26 AM -

The Family Day holiday was a messy one across parts of British Columbia on Monday as a series of Pacific low pressure systems began to move onshore.

Light snow began overnight on Sunday, gradually changing to rain as temperatures warmed above the freezing mark.

The next round of precipitation however, will likely be even heavier than the first, starting on Tuesday and continuing through early Wednesday morning.

"Significant rainfall is possible along the coast, while heavy snow is likely in parts of the Interior and in the high elevation mountain passes," says Weather Network meteorologist, Gina Ressler.

Upwards of 60 mm of rain is possible in the hardest areas with 15-30 cm of snow expected in some places as well.

"Total snowfall amounts from the system are forecast to be in a 15 to 30 cm range with highest amounts over the Coquihalla Highway," warned Environment Canada in a statement Monday night.

In addition, strong winds will give reduced visibility in blowing snow on the North Coast.

"Another weather system will approach the coast late Tuesday bringing more snow to the high elevation highway passes Tuesday night and Wednesday," EC adds.

As a result, motorists are urged to adjust driving habits and travel plans as necessary.

This is all part of a weather pattern called the Pineapple Express, which occurs when a strong area of low pressure develops in the Gulf of Alaska, just west of B.C.

"At the same time an area of very stable high pressure forms over to the south, centered near California," explains the Weather Network's Chris St. Clair.

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"The jet stream becomes very powerful between these two opposite air masses. The entire atmospheric flow in this region aids in drawing great amounts of evaporative moisture from the tropical Pacific. Much of it from as far away as near Hawaii. Hence the term Pineapple Express," St. Clair adds. "When this moisture laden air rises, by nature it cools and condenses."

Heavy rain can then fall for days at sea level, while steady snow falls in the higher elevations.

The good news is, this infusion of warmer air will lead to a warm-up across B.C.

Parts of the province have been under an Arctic Outflow warning for more than a week, and the province as a whole has shivered beneath bitterly cold temperatures.

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