Localized flooding is being reported from the Kettle River, Granby River, and Boundary Creek.
The Regional District of Kootenay Boundary, which has activated an emergency operations centre, says flooding was observed last evening and this morning.
Parts of Grand Forks, Greenwood, and the North Fork area are affected.
Some buildings, trailers and recreational vehicles are at risk, the RDKB said in a news release.
Residents in low lying areas are being urged to prepare for flooding by moving livestock to higher ground, turning off gas, electrical and water supply mains, and plugging toilets in basements and low floors.
If your home is at risk, sandbags are available for free. You can call 1-888-747-9119 to get the locations where they can be picked up and to arrange delivery of sand.
The RDKB says the rivers are predicted by river monitoring authorities to continue to rise and crest later this afternoon, however heavy rains and high temperatures could cause the rivers to rise.
The BC River Forecast Centre says the West Kettle River at Westbridge is flowing at 218 cubic meters per second, a 20-year flow.
The Granby River near Grand Forks is flowing at 320 cubic meters per second, a five-year flow. Both are expected to see additional rises today.