Hike Flattop Hallett Andrews Loop

10.9 miles 3238 ft gain  - Loop Trail

Added by Matthew Chang

Hike through the tundra, summit two renowned mountains, pass by three beautiful lakes, see a spectacular waterfall, and glissade down a glacier.

Bear Lake to Flattop Mountain

The trail starts at Bear Lake, where you get a view of Hallett Peak (12,713 ft) which will be the highpoint of your hike. After a short walk on the Bear Lake Trail, take the path to the right. After 1/2 a mile, take a trail left to the north. 1/2 a mile later, stay left at the trail intersection. If you follow the signs to Flattop Mountain, you should have no problem with navigation. The trail to Flattop Mountain (12,324 ft) winds through the forest with occasional views of the lakes below and the surrounding mountains.

At around 11,000 feet, vegetation transitions from forest to low-lying tundra shrubs and flowers. The trail switchbacks up a rocky slope. Rising to 14,259 ft, Longs Peak dominates the scenery to the south.

About 3 miles into the hike, the trail flattens out as you near the flat top of Flattop Mountain. Ahead of you, you can see the pyramid shaped summit of Hallett Peak. Hallett Peak is named after William Hallett, who helped create the first mountaineering organization in Colorado.

At just over 4 miles, you will reach the junction with the trail to Hallett Peak. This is a good point to check for thunderstorms. Afternoon thunderstorms are not uncommon in the summer. If you see any coming in the distance, head down the way you came. From this point on, the trail is much more difficult and you are prone to lightning.

Flattop Mountain to Hallett Peak

The trail to Hallett Peak is unmaintained and is easy to lose at places. If you lose the trail, just keep heading up towards the summit of Hallett Peak. You may have to do some minor scrambling up the talus slopes of Hallett Peak.

The summit of Hallett Peak rewards amazing views of the Continental Divide. To the south, Chaos Canyon lies below you and Otis Peak is a ridge jutting out to the east. Taylor Peak juts out behind Otis Peak. Your next destination is Andrews Pass which is the pass between Otis Peak and Taylor Peak.

Hallett Peak to Andrews Glacier

Hallett Peak is the turn-around point for a lot of people so don't expect to see people for the next few miles of the hike.

Travel over to Andrews Pass is all talus and no trail. Be careful where you step as some rocks may be unstable. As Andrews Glacier comes into view, head for the sign at the top of the pass. The sign reads:


Take note that glacier travel can be dangerous and crevasses may be present. If you choose to continue, carefully descend onto the glacier.

Andrews Glacier Glissade

glissade (ɡliˈsäd,-ˈsād) - a way of sliding down a steep slope of snow or ice

The top of the glacier isn't very steep and you probably won't slide very well. Continue down the glacier and you will notice a bulge at the center of the glacier.

Take out your garbage bag and get in. You are going to want a fairly sturdy garbage bag to prevent ripping. Slide to the right side (south side) of the bulge. When the glacier steepens, your glissade will go into full speed. You can slow your slide by digging your heels or hands into the snow.

Andrews Glacier to Glacier Gorge Trailhead or Bear Lake Trailhead

The glacier's slope flattens out near the bottom so your glissade will stop before you slide into the freezing glacial lake - Andrews Tarn. To the south of Andrews Tarn, you will find the Andrews Glacier Trail which leads down the valley. The trail runs adjacent to a Andrews Creek for 0.9 miles until it intersects with the Loch Vale Trail.

Take the trail left. The descent is about 3 miles back to Bear Lake. 1/2 a mile after the trail junction, you will arrive at The Loch. Following the signs to Glacier Gorge Trailhead, continue past The Loch for less than 2 miles and you will reach Alberta Falls. This is a popular destination for tourists hiking from the Glacier Gorge Trailhead. A little further down the trail is the Glacier Gorge Trailhead where you can take a shuttle bus. Or if you wish to complete the loop, the Bear Lake Trailhead is a short distance past the Glacier Gorge Trailhead.

  • In the summer, start early to avoid afternoon thunderstorms.
  • Check the weather before you hike.
  • Bear Lake may be very crowded during the summer. Park at the trailhead early or take a shuttle bus.
  • Use the shuttle bus that runs from Estes Park to and from Bear Lake and Glacier Gorge (shuttle buses only run in late spring, summer, and early fall).
  • Hike with at least one other person in case of an emergency. You will see less and less people as you travel from Bear Lake to Andrews Glacier.
  • An ideal time for a glissade is at noon. The glacier's surface is icy in the morning and mushy in the afternoon.
  • Bring a map and GPS. Snow can cover the trail long into the summer. I found that the Trails Illustrated Rocky Mountain National Park map is useful.
  • If you find that the low oxygen levels at high elevations hinder your performance, rest in between steps and make sure you are hydrated.

Where is the summit of Flattop Mountain?
The summit is at the intersection of Flattop Mountain Trail and the Continental Divide (about where the trail up Hallett Peak begins).

When are crevasses present on Andrews Glacier?
Usually, crevasses become present in the late summer when there has been lots of snowmelt. The crevasses don't disappear until the late fall/winter when the crevasses snow over.

Trail Mileage

Cumulative Distance (mi)Destination0.0Bear Lake Trailhead0.1Bear Lake4.4Flattop Mountain5.0Hallett Peak6.3Andrews Glacier8.2The Loch10.0Alberta Falls10.5Glacier Gorge Trailhead10.9Bear Lake Trailhead
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Leave a Review

Overall rating: 

🥇Top Contributor

5 months ago

Great views

Hallet Peak looks really gorgeous from this approach. Big climb to the top of Flattop


🥇Top Contributor

almost 4 years ago

Awesome views

Absolutely loved this loop. Great way to spend a day.


🥈 Contributor

over 4 years ago

Hiking Flattop

This is a great hike off of Bear lake in RMNP prepare to spend a whole day going up and coming down. The hike is pretty intense but it well worth the trip!

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