Opuntia columbiana

While on a field work venture along the Yakima River in central Washington I came across a patch of what I believe to be Opuntia columbia. I felt fortunate to have seen this patch before I walked into it as I was wearing light shoes. I was once no so fortunate while traversing an area above the Okanogan River.     

Patch of cactus on a high gravel bar above the river

I determined that the patch was broad enough and populated enough that it would be ok to extract a paddle.

Long thorns of Opuntia columbia?

I am nowhere near enough of a botanist to know if this cactus is Opuntia columbia, hence, my tentative identification. That said, I am pretty confident based on my review of Burke Herbarium. Desert Northwest provides a nice discussion of the various cacti species in Washington and discusses the botanical debates, but also comes down on this likely being Opuntia columbia. 

I enjoy seeing cacti in Washington State. Cacti do not have much of a presence in Washington even in the dry areas. This patch was growing on a cobble/gravel bar elevated above the river. The site is high enough that flooding must be very rare as there were some large ponderosa pines on the bar. The cobbles and gravel add to the dryness and have kept competition down just enough to allow the patch to thrive.