Tyndall Gully is the prominent couloir located between the summit of Hallett and Tyndall Glacier. (I've never actually heard it refered to by a name or seen anything written about it, so I don't know if it has an official name, so I'm calling it Tyndall Gully which seems appropriate. If anyone out there knows if it officially goes by a different name, let me know.) It's essentially an extension of the glacier but is mostly separated by a rib of rock, making it a distinct feature, especially during the summer months where it can been seen clearly from town. It's a fun but relatively short snow climb, given that it's a fairly long approach all the way to the end of Tyndall Gorge. Knowing that you can see it from just about anywhere in Estes gives it that "I've been there" factor which makes the long slog to the base worthwhile.
I soloed the route July 21, 2007 and the snow was soft, making for a straightforward ascent. The angle is for the most part moderate, but steepens near the top. Later in the season I imagine it would make for a fun alpine ice climb.
From the top of the couloir it's about a 15 minute walk to the summit.
Location
From the Bear Lake trailhead, take the trail to Emerald Lake. When you get to the shore of Emerald, look left for signs of the climber's trail and follow it up and right, above and around the lake until you get to the base of the massive rock buttresses where all of the classic rock routes are. From here, continue along the trail at the base of the cliffs and look for a good spot to break away right and head up the gorge a little left of center until you arrive at the base of the route, which will be obvious.
Protection
A good solo, but it would protect well with pickets or perhaps even a light rock rack for the sides of the couloir. Later in the season when it turns to alpine ice, bring some screws.