The B.C. River Forecast Centre has issued a high streamflow advisory for the Sproat and Somass rivers in the Alberni Valley region.
An “atmospheric river storm event” is expected to impact Vancouver Island on Sunday and early Monday, according to the forecast centre. Communities along the east coast of the Island as well as the Alberni and Cowichan valleys can expect heavy rainfall ranging from 50-160mm. Higher amounts are expected where upslope conditions occur, and slightly lower amounts along the eastern slopes of Vancouver Island. Temperatures are forecast to increase, and freezing levels will rise to 2000m. Snowmelt from mid-elevation may add to runoff for this event.
River levels are expected to rise through Sunday, with peak levels expected on Monday and potentially into Tuesday. Rivers flowing out of lakes are particularly susceptible due to the slow recession from last weekend’s storm event; these include the Somass River and the Cowichan River.
Hugh Braker, emergency management spokesperson for the Tseshaht First Nation, which has its headquarters on the banks of the Somass River, is advising people living along rivers or creeks in the Alberni Valley to prepare for possible evacuation of livestock or property. The Somass has been the scene of two major flooding events in the past few years.
“Storm paths can, of course, change. However, at this time, we appear to be in the crosshairs of a significant precipitation and snow melt event,” Braker wrote in a Facebook post.
The City of Port Alberni’s public works yard usually has a sandbag station set up in a corner of its parking lot on Sixth Avenue for people to fill their own sandbags.
Braker said he would be updating the flooding situation along the Somass and Sproat rivers via social media as he receives information.
The B.C. River Forecast Centre’s advisory also covers eastern Vancouver Island including Englishman River, Tsolum River, Oyster River and tributaries around Campbell River, Comox Valley, Parksville and surrounding areas.
Advisories are also in place for southern Vancouver Island for the Chemainus River, Cowichan River, Koksilah River and surrounding areas.