Severe weather prompts Enbridge oil pipeline closure

April 16 (UPI) -- Canadian energy company Enbridge said severe weather in the upper Midwest prompted it to close down one of its pipelines in Michigan.

As of Sunday, the company said its Line 5 pipeline system, which crosses the narrow Straits of Mackinac between the two Michigan peninsulas, was shut down because of a power outage at a terminal in Superior, Wisc. No outages were apparent in the region as of Monday morning local time.

"Out of an abundance of caution, Enbridge will be electing to leave the line down until the weather conditions improve at the Straits," it said.

The regional National Weather Service said a winter storm warning remains in effect until 8 p.m. local time Monday. Wind gusts of as strong as 30 miles per hour are expected, along with 4 to 6 inches of snow. Parts of Wisconsin got more than 2 feet of snow in a system that caused freezing rain and power outages across much of the region.

Enbridge has an agreement with Michigan's government to shut down the pipeline during periods of inclement weather. It closed the line in December when wind gusts as high as 35 miles were forecast, along with 9 foot waves in the Straits of Mackinac.

Line 5 runs through Michigan's Upper Peninsula, through the turbulent Straits of Mackinac and then east to Ontario. A restart is planned "as soon as possible." Most of the severe weather clears out of the area by Wednesday.

Last week, Enbridge confirmed three dents on Line 5 apparently caused by a passing vessel. The same incident apparently caused around 600 gallons of a coolant fluid to leak from submarine power cables in early April.

Enbridge said a review of its data show the structural integrity of Line 5 wasn't compromised.

The pipeline is a growing source of concern in Michigan. State agencies last year expressed concern with gaps in the protective coating on parts of Line 5 in the straits, at least one of which was caused when Enbridge installed new supportive anchors. Recent inspections revealed dozens of gaps across the span of the pipeline.