I am unsure where Marianne entered the water as her property backs right up to the banks of the Skykomish River. It seems a substantial river and may have been moving fast at the end of January.
Satellite view with house tagged and river edging the NE boundary of the property:
https://www.google.com/maps/place/1...2!3m1!1s0x549009dc32ed0f2d:0x26065b6da6076d09
Media reports state that she was found in the river quite close to home, 3 days after disappearing.
It looks like the picture you are showing is of the Snoqualmie River, not the Skykomish