Follow the obvious trail through the forest along the west side of Colchuck Lake (~5600'). On reaching the boulder field on the south end of the lake, follow cairns eastwards on a climber's trail up into Aasgard Pass. The trail is steep, steep and more steep - gaining 2200' in about 0.75mi, but is generally well marked with cairns (some being quite large). The route heads up passing climber's left of an obvious "tree island" in the center of the pass. Close to the top of the pass, the route traverses right/southwards and then climbs steeply upwards again to top out at about 7800' elevation. Expect some scrambly spots near the top. Given the steep terrain you may want to allocate some extra time for descending Aasgard. In 2005, under summer conditions, it took just about as long going down as it did hiking up.
If covered in snow, Aasgard Pass can be a very different experience and may require ice axe, crampons, and possibly even a rope for safety. Be aware that accidents and fatalities have occurred here - most often on climber's right of the "tree island" (aka the south side of the pass). The snowfields over there appear to be a shorter and more direct line to the top - but the terrain is steeper and, during spring melt, the solid-appearing snowfields can quickly become dangerous - having been actively undermined by running water. There may be little to no indication of when this transition occurs. Accidents have occurred here with individuals falling or glissading into open moats and crevasses generated by warming rocks and running water. This side of the pass may also have a greater rockfall potential. Sticking to the standard climbing route may be adviseable for safety.
Climbing route up Aasgard Pass
Aasgard Pass in snow
On reaching the top of Aasgard Pass, bear right/south and ascend a short ridge just west/above a small tarn (may be buried in snow in the early season). Your goal here is to reach the the obvious saddle area on Dragontail's eastern ridge
. Cross snow and boulders to the Snow Creek Glacier. The glacier is fairly tame with virtually no crevasses; guidebooks note it is about 30-degrees at its steepest. Make your way upwards wherever is easiest to the saddle area. Later in the season, you'll be able to exit the snow here and follow a faint climber's trail upwards to an easy scramble (class 3) to the summit above. Beware the sudden sheer drop off Dragontail's northern face directly down to Colchuck Lake far below.
It may be possible to combo Dragontail with other nearby peaks - including the Witches Tower
, Little Annapurna
, or to visit some of the beautiful lakes of the upper basin of the Enchantments - one of Washington's most scenic places.
Later in the season, one might be able to get by without, but an ice axe and crampons are probably a good idea for ascending the Snow Creek Glacier to the east ridge. Earlier in the season some parties may want to bring a rope and snow protection. There is some rockfall potential on Aasgard and below Dragontail's northerly ridge, so a helmet may also be a good idea.