Lyall's, or red-stemmed, saxifrage (Saxifraga lyallii) is one of the most common saxifrages in this area, and it can form dense tracts along the banks of snow-melt streams up high, and in places where water runs under the scree. Where it grows in number, it adds big swaths of colour!
It seems, from the USDA range map, that this tends to be a more northerly species:
http://plants.usda.gov/java/profile?symbol=SALY3
It's not one I've ever tried to grow... given its preferred habitat in the wild, I suspect it might not care much for the dry conditions in my yard... and I don't think I could do it justice, compared to how we see it in nature...