A powerful atmospheric river brought extreme rainfall to parts of Vancouver Island and the Lower Mainland this weekend, causing road washouts and widespread flooding. This is the most significant rainfall event since November 2021.
Effingham forestry station on Vancouver Island reported over 300 mm of rain since Friday. Several areas received a month’s worth of rain in just 48 hours. It marks the wettest day since September 18, 2004, and the second-wettest October day on record (behind October 16, 2003).
Compared to the record-breaking rainfall of November 2021, most stations across the South Coast recorded more rain during the 2021 event, except for Burke Mountain and Vancouver Harbour, which saw higher totals this time. Severe flooding affected areas like Coquitlam, West Vancouver, Surrey, and North Vancouver, with southwestern Vancouver Island also significantly impacted.
This atmospheric river had a more localized impact on parts of Metro Vancouver. Rainfall at Vancouver International Airport (YVR) is expected to exceed totals from the 2021 event. However, with less snowmelt this time due to the later season, flood risks were slightly reduced.
While Category 4 atmospheric rivers are uncommon for this region, this one is still less severe than the Category 5 event of November 2021, which extended into the Interior and the Sea-to-Sky corridor. These categories refer to the highest levels of moisture transport, often resulting in extreme rainfall and flooding.
Unlike this event, the 2021 system saw less of a rain-shadow effect on southern Vancouver Island and the Fraser Valley.