Canadian natural gas exports to the United States have been significantly reduced as a result of northern rainstorms that triggered an emergency inspection and possibly repairs on Alliance Pipeline to Chicago from British Columbia (BC) and Alberta, officials said.

Industry analysts predicted gas exports could be cut by as much as 500 MMcf/d, or 30% of Alliance’s 1.6 Bcf/d flow average.

The deluges caused hazardous shifting by a slope on the pipeline route along the Wapiti River, near the northern boundary between the two provinces in rough country west of Grande Prairie. Alliance posted a notice of possible service reductions last week and began work at the remote location Tuesday.

Alliance predicted the interruption would last three to five days but added the time-out could last longer if inspections turn up more damage and repair needs than expected.

The disruption is described as a setback by small to medium-sized gas suppliers such as Crew Energy Inc., which told shareholders all its Montney Shale production has to be temporarily shut in for the duration of Alliance’s service cut. Among big firms with diverse production sites and pipeline routes, Canadian Natural Resources Ltd. described the Alliance outage as “immaterial to our overall operations.”