OverviewArrowhead Arete is a striking formation that rises above Yosemite Village. The main route up its face is an adventurous 5.9 trad climb. Parties interested in climbing in should be aware that the routefinding (both on the approach and on the climb itself) is complicated and the should reserve a full day for the whole affair.
When Arrowhead Arete was first climbed by Mark Powell in the late 1950's, he called it 'the most continuously difficult free climb in the country' and rated it 5.8. The most recent Supertopo guidebook has inflated it to 5.9, a rating that most modern climbers would probably agree with.
Getting ThereThe approach to Arrowhead Arete is the first crux. Indeed, many parties interested in climbing the arete will be probably look at the 1,500' of steep ledges and gullies and wonder how you get up there without a rope in the first place. In general, you will want to find a climbers's trail that leaves the horse path just east of the large rockslide that is behind the NPS maintenance yard. Follow this up several hundred vertical feet to a section of sandy fourth-class terrain. Above this section, you will want to traverse to the left on trails of varying degrees of integrity, through more sandy and scary fourth-class sections, and finally up to the base of the arete. The climb begins at the bottom-left side of the Arete.
Since anyone attempting this route will (should) be using a published guidebook also, I will say here that the Falcon Guide and the Supertopo Guide to Valley free climbs offer indispensable beta on how to approach this route.
Route DescriptionArrowhead Arete begins at the bottom-left side of the Arete and the first pitch climbs some cracks to a stance belay at a gnarly tree. The second pitch is the crux, with thin stemming moves that lead into an offwidth (5.9). From the end of this pitch, continue up for another two or three pitches towards a large roof that is visible directly above. When you are approximately one pitch below the roof, traverse right on the face around to the right (east) side of the arete, where you will belay from a tree at the base of a prominent white flake. The white flake pitch is 5.7, and from its top there is fourth-class up and left to a large ledge. One more pitch from this ledge leads up to the spectacularly exposed "spike belay" at the very summit of the arete. From here, stay roped up over relatively easy terrain with some 5.6 and 5.7 moves across the knife-edge top of the arete and you head north towards the rim of the Valley. When the difficulties and exposure ease, unrope and start looking for the descent!
DescentFrom the unroping point on the arete, walk north--towards the rim of the valley--staying left until you can safely drop into the West Arrowhead Chimney. Descend the chimney (really just a gully up high) carefully, being sure not to knock any of the many loose rocks down on your partner.
There are three 80'+ raps in the chimney! You can not safely descend this route without a 60-meter rope. Two of the rappel stations are from slung trees; the third is from some fixed gear on the left side of the wall (as you are facing down). The third rappel brings you to the base of the route; from here retrace the approach route back to the Valley floor.
Essential GearA full trad rack is absolutely essential on this route, with many long slings and optional pro to 4" for the pitch two offwidth. The fixed gear on the route consists on a few old pitons (Supertopo, being typically exhaustive, shows their locations); there are no bolts and all anchors require trad gear except for the few where there is a tree to sling.
Don't forget your headlamp, regardless of what time you start the climb.