Terrace, B.C.- A flood watch has been issued for communities along the Skeena, Nass, Kitsumkalum river and other rivers and streams within these basins.

 

A strong high pressure ridge built over the Alaska Panhandle last weekend, producing record and near record temperatures across the north-west. Temperatures in Terrace on Tuesday, Wednesday and Thursday were above 30 degrees creating a rapid melt of the snowpack.

 

Continued hot weather is expected for today and Saturday, resulting in 7 days of continued heat. Current forecasts show the ridge migrating by Sunday, with a return to temperatures closer to seasonal normals by Monday.

 

Skeena River: The Skeena River at Usk (upstream of Terrace) has been rising steadily the last 3 days. Its current discharge is 5,100 cubic metres per second (m3/s), above the 2-year return period discharge of 4,800 m3/s. The water level has been rising at 6 cm/hr for the past 24 hours, and has risen 2.5 metres over the past 2 days. The water level is anticipated to rise another 2.0-2.5 metres, to a discharge near 6,500-7,200 m3/s, before peaking next Monday-Wednesday. As a reference, the peak discharge during the June 2007 flood event was 7,550 m3/s.

 

Nass River: The Nass River (at Shumal) has been rising steadily. Its current discharge is 3,500 m3/s, above the 2-year return period discharge of 3,400 m3/s. Its water level has been rising 2.5 cm/hr for the past 24 hrs. It is anticipated to rise another 1.5 metres before peaking near 5,500 m3/s by Monday-Wednesday.

 

Kitsumkalum River: There is no river level gauge on the Kitsumkalum River to provide quantitative information. However, based on discharge patterns on the Skeena and Nass rivers, it is expected that water levels on the Kitsumkalum have been rising over the past few days and will continue to rise through the weekend and into early next week. Flooding at Dutch Valley and other locations on the Kitsumkalum is expected (likely comparable to June 2007 flooding)