When off-trail routes are described, you’ll often see “go down a scree field” or “make your way through a talus slope. “
So what the heck is talus? What the heck is scree? And what the heck is the difference???
Technically there is no difference as defined by outdoor users.
However, most people, myself included, make a distinction between the two in outdoor circles. As has been the case for over two-hundred years.
The Oxford English Dictionary, states that the first recorded written use of the term “scree” was by the Reverend John Hutton in the glossary of his 1781 guidebook, “Tour to Caves” (2nd Ed.), in which he defined “scree” as small stones or pebbles and that the first recorded written use of the term “talus” was by the eminent English geologist Sir Charles Lyell in his classic 1830 treatise, “Principles of Geology.”
Note that the word scree has been defined longer than talus.
In general for common outdoor usage…
Scree is loose. Generally small sized rocks. I’d say up to a ping-pong ball or so in size at the most:
Talus is generally larger and can be loose or not:
As with the YDS classes, there is some gray area between what is scree and what is talus. And you’ll often find them gradually mixing into each other, too.
Overall summary: Among hikers, climbers, and outdoor users in general scree is loose and small; talus is larger and not nearly as loose as scree. You can often go boulder hopping with talus. You can “ski” a scree field.
And for the professional geologists who question this commonly accepted outdoors definition, don’t tell your IT person that the internet is down when you can FTP, access Usenet, email, and ssh into a server when you actually mean you can’t get to your Game of Thrones recap on YouTube. And please stop referring to monochromatic film on old movies or archival photos as “black and white.” 😉