The Coquihalla Summit is expected to be pummeled with rain over the weekend.
While no travellers are using the route between Hope and Merritt after severe flooding and washouts two weeks ago, there’s concern about the runoff that will come from heavy rain and melting snow.
A special weather statement issued this morning by Environment Canada says the Coquihalla Summit will see 40 to 60 mm of rain between Saturday evening and Sunday night. The system is part of a tropical storm system – now more widely recognized as an atmospheric river – which will lead to warmer-than-normal temperatures as well.
“Snowmelt will contribute to runoff, increasing the risk of flooding and possibly impacting vulnerable landscapes and infrastructure,” the special weather statement reads.
Snow basins at the Coquihalla Summit run into the Coquihalla River towards Hope and the Fraser River, and into the Coldwater River towards Merritt and the Nicola Valley.
Two weekends ago, when an historic rainstorm hit southern B.C., a rainfall warning was in place for the Coquihalla Summit with 60 to 90 mm of rain expected, though ultimately more than 230 mm of rain fell in parts of the province.
Parts of the Fraser Valley could also see more than 100 mm of rain by Sunday night, prompting the BC River Forecast Centre to issue a flood watch for “the Lower Mainland including areas along the Fraser Valley and areas around Hope.” A higher-risk flood warning is also in place for the Sumas River, with the risk once again for flooding to become worse in the Sumas Prairie in Abbotsford.
At time of publishing, there were no flood warnings, flood watches or high streamflow advisories in place for any waterways in the southern Interior.
However, City of Merritt officials are bracing for a surge on the Coldwater River, as CAO Sean Smith says the river could reach 130 cubic metres per second.
That would be more than double the peak seen on the Coldwater River during the spring snowmelt this year, but less than half of the rate that was reached during the peak of last week’s flooding.
Areas closest to the Coldwater River in Merritt remain on evacuation order, while properties along the Nicola River are also evacuated from about 20 kilometres west of Merritt to just east of Spences Bridge.