A flood watch has been issued for the Skeena River, which is threatening to overflow. (CBC)

Several hundred northwestern B.C. residents will likely spend the weekend sandbagging after a flood watch was issued for the Skeena River, which is threatening to overflow its banks.

Bill Kuhnke with the B.C. River Forecast Centre said an above-average snowpack in the surrounding Coast Mountains combined with the recent heat wave in B.C. is to blame.

"With this very warm weather that we're experiencing, the snow is quite ready to melt and is melting quite rapidly, and that's resulting in rapidly rising levels in the rivers in the area," said Kuhnke.

The Skeena River had already risen 2.5 metres by Friday morning and was expect to rise another two metres or more by the time it peaks sometime between Monday and Wednesday next week, according to forecasts.

Residents of about 200 homes in low-lying areas of Terrace have been told to sandbag around their houses. Rod Ames told CBC News he was wasting no time getting ready.

"We are concerned. That's why we got sand delivered already. They just declared a state of emergency, so the fire department just got funding today," Ames said.

Flood watches are also in place for the nearby Nass and Kitsumkalum Rivers, as well as the Stikine River near the community of Telegraph Creek to the north, and the Liard River near the community of Lower Post, also in the north.