VANCOUVER - A flood warning has been posted in British Columbia's southern Interior for the Chilcotin River following heavy rains.

The Chilcotin is a tributary of the Fraser River and experts say the surging flows could further complicate efforts to save returning salmon already hampered by a large slide downstream on the Fraser.

The River Forecast Centre issued the warning for the length of the 250-kilometre Chilcotin River late Monday after the region was drenched by more than 90 millimetres of rain in less than a week.

The centre says the river could peak Tuesday, but the danger remains with riverbanks unstable and the waterway flowing above the 200-year return period.

Runoff and debris from the Chilcotin empty into the Fraser just north of Big Bar where a recent slide has severely constricted the river, hampering returns of chinook and sockeye salmon.

Geotechnical engineers have already said weather conditions over the weekend challenged workers trying to clear rock and debris at the slide site in order to get better assess to environmental hazards for the fish.

Fisheries Minister Jonathan Wilkinson is expected to visit the landslide incident command post Tuesday and get an aerial view of the pinch in the river, which he has described as a key priority for the department's Pacific region.