High Streamflow Advisory

igh Streamflow Advisory Update:  North Coast, Central Coast

(including Bella Coola, Kitimat, Terrace, Stewart)

A very warm and wet frontal system with a moisture feed from Tropical Storm Neki arrived on the North Coast and Central Coast overnight.  Environment Canada issued a Rainfall Warning yesterday for coastal and inland sections of the North Coast, and has expanded the warning area this morning to include coastal and inland sections of the Central Coast.  Rainfall amounts of 100-150+ mm over 24-36 hrs are expected in coastal areas, and 50-100+ over 24-36 hours in inland sections.  The storm appears to be sufficiently moist that higher rainfall amounts may occur in some areas. Water levels on some gauged rivers in the affected area have just begun to rise.  Rivers throughout the area are expected to now rise steadily through to late Friday. Flooding on some rivers in these areas is possible by Friday.

The early precipitation from this event occurred as snow; however, temperatures have been rising with the arrival of the warm front.  The Burnt Bridge Creek snow pillow, located at 1330 metres elevation in the Bella Coola drainage, has seen the temperature rise from -1¬∞ at 7AM to +4¬∞ at 11AM today.  With the rising freezing elevation today and tonight, we anticipate that most of the early season snow accumulation along the Central Coast will melt by Friday night, adding to streamflow.

The Burnt Bridge pillow site has recorded 42 mm of precipitation over the last 12 hours.  Ministry of Transportation road weather stations have recorded 30-50 mm of precipitation over the last 12-14 hours, with 50 mm recorded at Bella Coola, 20 mm near Stewart, and 30+ mm in the Kalum River valley near Terrace

River levels have just begun to rise.  There is potential for high flows on the Bella Coola and Salloomt rivers, and other rivers in the Bella Coola valley; Owikeno River (First Nation community downstream of Owikeno Lake); Kitimat River and Hirsch Creek (near Kitimat); Kalum River (Dutch Valley) near Terrace,  Bear River at Stewart, and others.  The forecast for high rain magnitude and intensity, combined with the melting snow, results in likelihood for flooding on some rivers in some areas.

The River Forecast Centre will provide an update by 10AM Friday, or earlier if conditions warrant.

River Forecast Centre
Ministry of Environment
Water Stewardship Division

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