Flooding possible as significant rain, runoff expected for most of Newfoundland

A weather system moving over Newfoundland is expected to bring substantial rain beginning Thursday, and Environment Canada warnings are in effect for the entire island. 

With the rain comes mild temperatures and concerns of significant snow melt, according to Environment Canada meteorologist Rodney Barney.

Southern and western Newfoundland could see as much as 50 to 90 millimetres of rain, and possibly 130 millimetres over higher elevation areas by Friday evening, Barney said. 

"Especially on the west coast, where there's a lot of snow on the Long Range Mountains right now, you add that amount of rain to it along with those mild temperatures, it could produce some fairly significant runoff," he said. 

Environment Canada has issued rain and wind warnings for the western portion of the island, noting heavy downpours are likely to cause flash floods and water pooling on roads and the possibility of localized flooding in low-lying areas.

Eastern Newfoundland will also see a portion of that rain and mild temperatures. About 20 to 30 millimetres is expected to fall over Thursday and Friday with a high of 10 C.

But the biggest concern will be the wind. Environment Canada has issued a wind warning for the area.

Barney said Thursday will be gusty on the Avalon Peninsula, but come Friday winds are expected to reach about 110 km/h.

"That combination of rain, wind and warm temperatures is going to lead to a lot of snow melt [and] a lot of runoff over the next 24, 48 hours," he said.

"Everywhere on the island is going to see some impact from this."

Southern Labrador will dodge the rain but can expect more snow. 

Barney said about 30 to 50 cm is expected to fall near the Strait of Belle Isle, tapering off the further it moves north.

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