Oh my goodness are you ready for a dazzlingly beautiful hike? The Carthew Alderson trail is one of the most scenic (and varied) hikes in Waterton Lakes National Park in Alberta, Canada. It’s a one-way walk, so most people take a shuttle to Cameron Lake and the trailhead, then hike back to Wateron Park townsite. This trail is quite long, and has a few strenuous moments near the start, but the rewards are well worth the effort; You’ll hike past 6 jewel-like subalpine and alpine lakes, 2 waterfalls, through subalpine forest and meadows as well as past argillite scree slopes and a high ridge. You even have an optional jaunt to a summit with incredible views towards Glacier National Park in Montana.

Carthew Alderson Trail Map

Carthew Alderson Trail – the basics

Distance: 19-20km
Elevation gain: 900m (depending how you measure it) 
High Point: 2356m (Carthew Summit)
Time: 6-7 hours (we were moving for 5 hours according to strava)
What to bring: The 10 essentials, and bring bear spray
Facilities: There are loos at the trailhead, at Alderson Lake campground at at the finish by Cameron Falls.
Cost: You’ll spend $20 on the shuttle, plus you need to have a Parks Canada Pass.
Dogs: Dogs are allowed (on leash)
How hard is it? Challenging – the trail itself is not technical but it is quite long, so might be tough if you are not used to hiking 20km in a single day. It feels more like intermediate if you are used to long hikes.

Carthew Alderson Trail – Getting started

The best way to do this trail is end to end. Use the hiker shuttle to get you to the start, then walk back to Waterton Park. The shuttle leaves from outside Tamarack Outdoors (a hiking shop and cafe, in case you need coffee…) everyday at 7:30 and 8:30am. You can book here ($20). It’s possible to bring doggos on the shuttle.

Cameron Lake

The trailhead is at the beeeautiful Cameron Lake, at the end of the Akamina Parkway. This means you get this fabulous view of Mount Custer and Forum Peak before you even start putting any effort in!

Switchback time!

The start of the trail takes you into the trees and up some switchbacks. They are pretty long (and not too steep) so although you gain 300m-ish, it is spread over 3km.

Kenow Wildfire

As I’ve mentioned in my last few posts, Waterton Lakes National Park was severely affected by the Kenow Wildfire in 2017. You’ll notice the burned areas pretty quickly into this hike, and then again as you approach Waterton Park townsite at the end.

It’s pretty sad to see such a large area that has burned; The surrounding mountains looks sort of beige in the early morning light. But it is pretty cool to see the thousands of wildflowers and berry bushes in between the trees.

After the first 3km the trail flattens out. Hike into the meadows, up to a giant pink boulder.

Summit Lake

The second lake of the day is Summit Lake. If you’re lucky you’ll get to see Chapman Peak reflected like a mirror. The border is about 1km south of here, so that Mountain is in Montana (USA.) Hellooo American friends!

Once you leave Summit Lake, the trail ascends towards Carthew Summit, the highest point of the day. You can see Chapman Peak, Mount Custer, Kintler Peak and Kinnerly Peak.

It’s really interesting to see the burnt trees up here. It looks like since they lost their foliage, they all got toppled in an avalanche. They all curve and lean down the hill.

As you climb higher, the trees give way to ground-hugging wildflowers, then to pink scree slopes. There are 3 hefty switch-backs to get you up the Carthew Summit (which isn’t really a summit – it’s the saddle between Mount Carthew and Mount Alderson.)

There are a few shortcuts straight up the switchbacks to Carthew Summit, but it’s better (and easier) to stay on the main trail. Once you’re up on the saddle, there is an optional side-quest to Carthew Summit Overlook. I recommend doing this – it’s only an extra 300m each way.

Watch out for marmots! We spotted this fella sun bathing just below the overlook.

Carthew Summit Overlook

This is the view south from the Carthew Summit Overlook. The lakes are Lake Wurdeman and Lake Nooney, and Summit Lake, where we’d just been.

Somehow we overtook the other hikers from our shuttle, so we had these amazing views all to ourselves.

This is the view southwest. The ridge in the foreground is part of Mount Alderson. You can see Mount Richards peeking up behind it to the left. The big mountain in the middle is Campbell Mountain (in Montana.)

Continue towards Carthew Lakes

Carthew Summit is the saddle between Mount Carthew (left) and Mount Alderson (right.) This trail goes past those three bright blue lakes and all the mountains in the photo below. Waterton Park townsite is to the right of those two mountains in the middle in the distance (Mount Crandell and Bertha Peak.)

Geology – Argillite

As I mentioned in the post about Bertha Lake, the rocks in this area are argillite. This is a sedimentary rock that was made from mud that didn’t have quite enough pressure or heat to turn it into slate. The red/pink colour is due to oxidized iron. You can read more about the cool geology of Waterton Lakes here.

They were a little far away, but we saw a group of bighorn sheep grazing on the snow-patchy slopes of Mount Carthew.

Carthew Lakes

The alpine lakes along this route are stunning. Even in August, there was snow at the top of the highest lake. To stay on the trail, walk along the left of the upper lake.

The middle Carthew Lake is surrounded by small trees and shrubs and wildflowers.

There are a few little waterfalls between the upper and middle lakes.

We stopped at the middle lake for lunch. There were plenty of butterflies as well as a white-tailed ptarmigan with her chicks. We did see other hikers along this trail, but the groups were far enough apart that we got to see so many critters along the way!

Hike along the cliffs below Mount Carthew and continue around the middle lake.

After that, the trail curves around the corner and starts to descend between Mount Carthew and Buchanan Peak. Look at these magnificent views!

There is one big switchback turning you towards Mount Alderson. You hike down 2km through this awe-inspiring narrow valley. You can clearly see the sedimentary layers of rocks. They erode into scree, so you need to be careful as it’s easy to slide down these slopes.

This is Marc’s view looking back at Mount Carthew from below. There is another tall waterfall here that cascades down the cliffs below the lowest Carthew Lake.

Alderson Lake

The final lake of the day is the beautiful deep blue Alderson Lake. It sits below the steep cliffs of Mount Alderson. There is a campground (and a beach) on the far side of the lake.

I would love to come back and camp here! We stopped to cool down our feet and enjoy feeling small between all these giant Rockie Mountains.

Heading down

Once you leave Alderson Lake, you have another 6.5km of pretty easy downhill hiking to get back to Waterton Park. As you hike down, it seems like there are four different mountains across the valley. In fact, these are all just off-shoots of Buchanan Peak and Buchanan Ridge.

The last several kilometers go through burned areas on the north slopes of Bertha Peak.

In the late afternoon, these skeleton trees are bleached by the sunlight so the few trees that survived the fire really stand out. I’ve never seen views quite like this.

Once you’ve hiked the whole way down the valley, you turn the corner to see Waterton Lakes, the Waterton Park townsite and the Bear’s Hump, (a viewpoint on Mount Crandell, below left.)

Mount Crandell was almost completely stripped by the wildfire. It makes it easy to see the layers of geology. The path joins up to Cameron Creek, so you’ll see a few small waterfalls.

Cameron Falls

The trail finishes at Cameron Falls. This fabulous waterfall can turn pink on rainy days when the water washes down iron-rich water from the mountains above.

I know I already shared too many photos, but I’ll still finish with a whole bunch of panoramas so you can see what to expect on this amazing hike. If you are curious what this looked like before the fire, this post from enjoy your parks is really great.

The Carthew Alderson trail is brilliant! It’s not often that you get amazing views for an entire 20km hike! This was the best hike we did in Waterton Lakes National Park in terms of wildlife and variety of the landscapes. Do you fancy it?