Alderson-Carthew is a One-Way hike from Cameron Lake to the Waterton townsite. It is about 16km long and takes between 5 to 7 hours depending on your urgency. The highest elevation is about 7500ft(2300m) roughly, as map and other guides seem to vary on what the actual elevation is but this can be said for all ridges, peaks and summits in Waterton Lakes National Park. It is recommended that you take a shuttle from the townsite or have a friend drive you to the start of the trail. PLease check at the front desk of your hotel or the information centre at Bear's Hump what is available. The trail for Alderson-Carthew begins at Cameron Lake. You start off through the forest encountering many long switchbacks as you make your way to Summit Lake. Just before you reach Summit Lake it opens up immensely and once past the small lake you now continue on a narrow trail up to Carthew Summit.
The surface also changes as the solid ground is now rather loose screed and you may pass through the remains of some avalanches that occurred the past winter, again this depends on the time of year, if you visit in August or September the remains may have completely vanished. As you make your way up to the summit, the trail forks off in 2 directions, to the left it continues towards Carthew Lakes and to the right it continues Summit. It can be very windy at the summit and temperature can be a bit cooler even if it is not on the lower slopes so take care on the summit. You make your descent towards the 3 Carthew Lakes, Upper, Middle, and Lower. The way down is on a steep slope of red screed and can be a little nervy for people you aren't that agile on their feet but nonetheless fun to do. The trail now continues around the lakes on a rather narrow path and again snow can be met, hindering your way along the lake edges. The lakes are very picturesque and they are bordered by Buchanan Ridge to the left and Alderson and Bertha Peaks to your right as you make your way down.
Once the Carthew Lakes are behind you, you now make your way down towards Alderson Lake. It can be see in the valley and a small waterfall greets you as you make your descent towards Alderson Lake. The trail down is a little steep and rocky but nothing too strenous. The further down you go, the more immense the cliff face of Alderson becomes. Once past Alderson lake you have abother 6 to 7km to go. You make your way down through a dense forest but on a clear, uneventful trail until you are parallel with the Akamina Parkway. In the final 1km, the trail has a barrier to your left along a rapid stream that flows towards Cameron Falls and where the trail ends in the townsite. The elevation gain is about 2200ft from Cameron Lake to Carthew Summit. The elevation lost from Carthew Summit to the townsite is roughly 3400ft.