Flood watch, evacuation alerts ended in B.C.’s Fraser Valley

From March 20: Dozens of homes along the Chilliwack River remain under an evacuation alert due to higher river flows following days of heavy rain.

The B.C. River Forecast Centre has downgraded its flood watch and the Fraser Valley Regional District has lifted evacuation alerts as the South Coast continues to recover from the severe atmospheric rivers that struck earlier this week.

Residents of 30 properties along the banks of the Chilliwack River were told to be ready to leave at a moment’s notice during the height of the storm Thursday afternoon.

At that point, a flood watch was in effect for river systems throughout the Lower Mainland.

On Saturday morning, the forecast centre downgraded its flood watch to a high streamflow advisory. In the afternoon, the FVRD followed suit, rescinding the evacuation alerts.

As much as 300 millimetres of rain fell from Monday through Friday in parts of the Lower Mainland, with the highest totals recorded in Howe Sound, the North Shore Mountains and in the Fraser Valley, the forecast centre said in a statement Saturday.

This precipitation was augmented with up to 100 millimetres worth of rainwater equivalent from melting snow, according to the agency.

“Rivers across the region continue to recede following the peaks observed in the past few days,” the statement reads. “Flows in larger and lake‑fed river systems remain elevated but are expected to continue easing through the weekend and into next week.”

The storms caused multiple landslides and led to the declaration of a state of local emergency in the FVRD.

The regional district said receding river levels prompted the change Saturday, but added that evacuation alerts could be reissued if circumstances change.

“The FVRD would like to remind residents to stay safe and take precautions during this time,” reads an update from the district’s emergency operations centre.

“Please stay away from swift-running rivers and unstable banks. Due to the soil saturation, expect possible erosion and debris slides.”

Under the river forecast centre’s warning system, a flood watch means rivers are approaching and may exceed “bankfull,” causing flooding in nearby areas.

A high streamflow advisory, by contrast, means rivers are high, but “no major flooding is expected.”