This is an awesome route with spectacular views and position the whole way. It protects very well, and there is no shortage of belay opportunities. The first ascent was by Dick Long and friends back in 1957 (finally, an obvious Sierra line that was not
first climbed by Norman Clyde!).
Due to the moderate level of difficulty (much of the route is class 3/4) it is often soloed. A combination of the North Ridge and West Ridge is also common, as the North ridge serves as a very good approach to the West Ridge. Whether roped or otherwise, taken on its own or as part of a longer day, the West Ridge is well worth the effort it takes to get to it.
The moderate difficulty also makes it well suited to climbers who are new to alpine climbing, though due to its length, you will want to pay attention to the time. There is no good way to bail, although dropping down into the gully on the north side will provide you with a class 3 way of completing the route, or downclimbing, depending on which way you need to go. It's a lousy option if it starts raining. In that case, you must stay on the ridge.
ApproachThere are many ways to approach the route, which begins at the toe of the west ridge at about 11,000 feet. The most interesting (and possibly the most efficient) way is to simply climb the North Ridge, then descend the third class south side to the summit plateau, and thence down to the base of the ridge as described below.
The most commonly used approach simply follows the East Ridge route to the summit plateau. Basically, you start out at or near Sawmill campground and head more or less west up the broad canyon. If you hit the western skyline first, turn right. If you hit the northern skyline first, turn left. Once at the summit plateau follow the ridge on the west side south and then southwest until it is possible to drop down a class 2/3 gully to the basin beneath the imposing South Face. Be sure you can see all the way down. If you can't, keep going--the first few gullies cliff out.
It is also possible to start in Tuolumne Meadows, taking either of two trails that lead to Young Lakes. From Young Lakes the ridge is plainly visible; contour up canyon to the base of the ridge.
Allow 3-5 hours for the approach, depending on whether you are a fast or slow hiker, and 2-3 hours for the descent. Climbed unroped, the route will take less than two hours. Simulclimbing will slow you down some, but not as bad as pitching it out. Simuling is a commonly used strategy on the upper ridge--just be sure to have a few pieces in at all times! Add additional time based on your planned strategy, and your typical rate for pitched climbing. There are probably two roped pitches at the start, and maybe a couple more higher on the ridge. It all depends on your tolerance for risk.
Peter Croft's description of this route is right on. At the base of the west ridge there is a large alcove a few hundred feet high. Although one can climb anywhere one likes, the "standard" route follows the left-hand crest for approximately two pitches (if climbing roped) to the apex. From there, follow the ridge, staying on the crest as much as possible. When difficulties or exposure get to be more than you bargained for, dropping down on the north (left) side a bit will usually drop the difficulty to class 3. Secor's 2nd Edition contains a photo with the "standard" route illustrated.
Due to its length (about 1,800 vertical feet), it would be inadvisable to attempt this route with a plan to pitch it out the entire way. After the initial pitches most of the route is class 3 or 4, so this shouldn't be necessary. There are occasional spots where the difficulty is low class 5, or simply very exposed. Some parties will want to rope up for these sections.
If soloing, all you need is a pair of rock shoes and a little food and water. If you're not absolutely confident in your ability to climb 5.6-ish (it's not hard to stray into harder territory) then you'll need to bring a rope. A single set of cams and a few nuts will suffice. Bring some slings, including some double length ones. If the forecast (or the sky, despite what the weatherman says) includes the possibility of thunderstorms, go find something else to climb--it's hard to bail off this route, and you will be very exposed to the elements.
Because of its position on a ridge, and generally sound nature of the rock, there isn't much danger of rockfall on the route. The class 3 chute on the approach is probably more dangerous from that perspective, so a helmet might not be a bad idea.
Ice axe and crampons may be needed for the approach in spring and early summer.