Warm and wet weather forecasts are prompting warnings for Interior waterways and highways in B.C. this long weekend.

The BC River Forecast Centre has issued a high stream flow advisory for the southern Interior including the Okanagan, Thompson, Boundary and Similkameen regions.

The centre said unusually high temperatures in those areas have led to a rapid snow melt, prompting rivers and streams to rise.

Glacier National Park

The saturated ground already set off a mudslide on Friday that caused a partial closure of Highway One through Glacier National Park between Golden and Revelstoke. The route was reopened Friday afternoon. (Parks Canada)

Dave Campbell, the head of the forecast centre, said the high streamflow advisory is the lowest level of its three-step warning, and indicates that the rivers are getting higher and there's a concern for flooding on smaller creeks.

The July-like warm weather combined with the possibility of heavy rain from Bella Coola, to Kamloops and south to Nelson raises concerns, Campbell said.

"There's a bit of a triangle, that could see 20 or 40 or even more millimetres of rain through the weekend and so if the rivers already higher, and some of those smaller creeks are fairly high, there's not a lot of extra room. So if we were to get a real bulls-eye of lots of rain in localized areas that could cause local flooding."

Friday mudslide cleared

The saturated ground already set off a mudslide on Friday that caused a partial closure of Highway One through Glacier National Park between Golden and Revelstoke.

The Transportation Ministry warned that the warm, wet weather is affecting mud flow activity and that may require highway closures this long weekend.

Campbell said the early melt of snow could help mitigate possible flooding in June, when the larger rivers start to swell.

"It might be a bit of short term pain on some of those smaller rivers, but I think in terms of the bigger rivers — like the Fraser or the Thompson — that's really starting to flush out some of that winter snow pack. That helps to ease the risk a little bit, so long as it doesn't bring the river up too much."

With files from the Canadian Press