More than a drop in the bucket: last week’s deluge in context

A number of rainfall records were broken in the Fraser Valley during the unruly once-in-a-century weather system and Environment Canada has forecasted three more atmospheric rivers to hit the region in the coming days. But before the focus shifts on what’s to come, let’s put into context the historic nature of the recent catastrophic weather that led to copious amounts of flooding, which forced thousands to flee their homes, and destroyed major transportations networks leaving the Lower Mainland cut off from the rest of the country.

On average, during the entire month of November, Abbotsford, Agassiz and Hope receive about—or close to—a foot of rainfall, or just under in the case of Abbotsford. But the communities recorded more than half that amount during last week’s three-day storm.

In a single day, on Nov. 14, Hope received five times more rainfall than its previous Nov. 14 record (registered just years ago in 2018—35mm), and triple its previous high from any other single day. It was the hardest hit community during the storm. Cumulatively, slightly less than a foot of precipitation (252mm) was recorded.

To put this into context, Kamloops typically gets about a foot of precipitation annually (278mm), Hope was hit with nearly that amount in a single day. Not far behind was Chilliwack and Agassiz, which each received about three-quarters of a foot cumulatively.

Like Hope, Agassiz, Abbotsford and Langley also shattered long-standing rainfall records. Agassiz saw half a foot (127mm) of rainfall, crushing a record set 125 years ago in 1896 (61mm), while Queen Victoria was in reign. Abbotsford (100mm) and Langley (91mm) also obliterated their previous rainiest days on record: Abbotsford and Langley’s previous records were both 78mm, and both recorded in 2004 (78mm). Environment Canada notes the summary of weather information is preliminary and it does not account for a complete or final report.

Another atmospheric river is expected to make landfall in the valley on Thursday, followed by a second one on Saturday, and then potentially a third one on Tuesday. Meteorologists warn the rainfall will hinder recovery efforts, given the already inflated rivers and saturated grounds. Fortunately, the latest string of atmospheric rivers aren’t expected to bring the historic rainfall levels that were seen last week. But if another half a foot of rain falls in Abbotsford before the month’s end the city will have reached another milestone – the wettest month on record, collecting nearly a foot and a half of rainfall.