‘Mini-Pineapple Express’ bringing 48-hour deluge to B.C.’s South Coast

Residents of B.C.'s South Coast are bracing themselves for the arrival of a 'mini-Pineapple Express' off the Pacific Ocean this morning, which is expected to drop up to 150 mm of rain in the area by Saturday morning.

Rainfall warnings are in effect for West Vancouver Island, as well as Metro Vancouver, Howe Sound and the Sunshine Coast. Rainfall amounts of up to 150 mm are expected around Tofino, on the west coast of Vancouver Island, with the bulk of that falling tonight and through Friday. On the mainland, the heaviest rainfall will be through Howe Sound and the Sunshine Coast, which are expected to see 60 to 100 mm of rain by Saturday morning. Metro Vancouver is expected to see slightly less, from 40 to 80 mm over the next 48 hours, with the highest amounts in the North Shore.

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A true 'Pineapple Express' — an unofficial meteorological term — is a storm system over the Pacific that draws a nearly straight-line river of moisture from the Hawaiian Islands to the west coast of North America, typically impacting on the U.S. Northwest and B.C.'s South Coast. This system taps into an abundant supply of tropical moisture and can deliver days of torrential rainfall along the coast and then heavy snowfalls in the mountains as it moves further inland. The warm air being carried with the storm usually makes short work of this fresh snow, melting it almost as quickly as it produced it, and areas east of the mountains usually enjoy a warm 'Chinook' as the system presses eastward.

This storm isn't a true Pineapple Express, because it is drawing its moisture from further north and east of Hawaii. However the north Pacific has been unusually warm this winter, so the region the storm is drawing from has more moisture in the air than is normal for this time of year.

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The rainfall from the system is expected to slowly increase throughout the day today, with the highest amounts falling tonight and through the day on Friday, before gradually tapering off Saturday morning. Areas further inland should check for updating warnings due to the potential for heavy rain and snow in the mountains.

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