Kelowna, in British Columbia is situated in a broad valley between mountain ranges west of the Continental Divide. Thus, is it subject to having its natural draining from mountain ranges change, without warning or predictability, during the hour of the shift. Compression occurs during the subduction of plates driving under the land to the west of the Continental Divide, and in a valley where drainage is already essentially blocked due to skirting ranges, this has the potential of creating a large inland lake, already forming at Kelowna. All that it would take to create this situation is a rise in foothills where drainage currently occurs, or a closure of a pass such that river water finds it can no longer do more than seep through. The jolting and heaving that occur during mountain building can affect the current drainage along a long river at many points, even distant, causing a backup of water to the lowest level, already situated at Kelowna, on the shores of the lake that carries drainage from the skirting mountain ranges. Thus, those in the township of Kelowna should at least plan on not having their housing intact, but moving into houseboats to take advantage of a larger inland lake, should this occur.