ApproachChances are, you are only going to be doing this route if you have come up from Snow Lakes. If you came up via Aasgard Pass, it makes no sense to climb down the other side of the Enchantments to do this route. So, I will assume you are coming up via Snow Lakes.
The Snow Creek Trailhead is accessed via Highway 2 in Leavenworth, WA. On the west side of Leavenworth, turn south on Icicle Creek Road. It's about 4 miles down this road when you come to a large parking area on the left that is identified as Snow Creek Trailhead.
Take this trail up past Snow Creek Wall. At 6.5 miles you will reach Snow Lakes, a good place to camp if your permit is only for this area. From Snow Lakes, continue up the trail from the west side of Upper Snow Lake that climbs up to the Enchantments. Continue on through the Enchantment Lakes until you reach Perfection Lake. At the point between Perfection and Sprite Lake, turn left and go through between them. Follow a faint climbers path on the south shore of Perfection Lake at the base of a small hill on the left. Just past Perfection Lake it flattens out and there is a nice trail that goes down to Crystal Lake. We cut northwest from the point where the trail starts descending to Crystal Lake and went cross country to a large boulderfield at the base of Little Annapurna's southwest face (it's also a hundred yards or so directly north of Crystal Lake across a small swampy area). It doesn't really matter which way you take it as you really end up going down to the north side of Crystal Lake anyway.
Route DescriptionFrom the boulderfield at the base of Little Annapurna's southwest face, the cliffs appear to be a shallow cirque. Look left (west) to find the obvious rock gully ascending to a notch about 200 feet above. This photo was taken from the point on the trail before descending down to Crystal Lake but you can see the rock gully just right of center that is shaded.
Ascend the rock gully (mostly Class 2 and the boulders are fairly solid, not loose but still be aware of the possibility they will move on you -- there is one Class 3 move on the right side near the top). From the top of the notch, head right (north) up the shallow rocky slopes and then left (northwest) once you see the summit. There are cairns in some spots but basically pick your way on the easiest route you can see. You could possibly get "treed" on some slabs but nothing too bad that you can't downclimb and go around easily. A climbers path gets evident about 2/3 of the way up from the notch and takes you to the summit.
To descend, unless you camped at Crystal Lake in which case you would simply downclimb the same route, you will want to head down the trail on the northeast side of Little Annapurna that comes up from Isolation Lake. If you go too far left though, you will end up going over towards Witches Tower which is where it can get steep and in fact one person fell off the cliffs above Isolation Lake and died. We ended up sliding down what is left of a section of the Snow Creek Glacier (which may not have been the smartest thing to do as it was icy and steep and melting out underneath). SP member Dean also mentions downclimbing directly northeast on the slopes down to the basin which is the normal way up from Aasgard Pass in this route page.
Total distance is a little over 10 miles from the Snow Creek Trailhead with an elevation gain of about 7300 with all the ups and downs.