Canada: Evacuation orders in place following landslide and possible flooding on Chilcotin River, British Columbia, July 31

Evacuation orders are in place following landslide and possible flooding on the Chilcotin River in southern British Columbia as of late July 31. The Cariboo Regional District has issued two evacuation orders in the Chilcotin River area due to a landslide in the Farewell Canyon area early July 31, affecting at least 58 properties. Residents evacuated north to Highway 20 and east into Williams Lake. One person was injured in the landslide. The Chilcotin River is fully blocked, and there is a risk of flooding. The Thompson Nicola Regional District issued precautionary closures of the Big Bar and Lytton ferry services on the Fraser River due to the landslide.

British Columbia has issued an emergency alert for anywhere on the rivers or along the banks of the Chilcotin River, from Hanceville to the Fraser River, and the Fraser River, from the Chilcotin River to Hope, due to the risk of flooding and landslides; people should evacuate the area immediately. A flood warning is in place for the Chilcotin River upstream of the landslide in the vicinity of Farwell Canyon, while a flood watch is in effect for the Chilcotin River downstream of the landslide in the vicinity of Farwell Canyon and the Fraser River from the Chilcotin River confluence downstream to Hope. A high streamflow advisory has been issued for the Fraser River downstream of Hope.

Sustained heavy rainfall could trigger further landslides in hilly or mountainous areas, especially where the soil is already saturated from previous downpours. Heavy showers could also trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall.

Authorities could issue further mandatory evacuation orders for landslide-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Road closures are likely within and around areas where mandatory evacuation orders have been issued. Further landslides could block sections of roads and railways in the affected region. Residents' return could disrupt traffic flows after authorities lift evacuation orders.

Flooding triggered by heavy rainfall could also render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.