Take a Walk: The Glacial Lake Missoula High-Water Mark


The area we inhabit today, the Missoula Valley, used to sit deep under a massive body of water.

It is hard to believe, but there is scientific proof. This body of water, now known as Glacial Lake Missoula, was created around the end of the last ice age about 15,000 years ago and, at its maximum height, reached 4,200 feet in elevation.

The significance of that number today and the historical ice age event has been permanently marked with engraved stones on well-known hiking trails on Mount Sentinel and Mount Jumbo.

One of those hiking trails happens to be located just outside my front door, which is a benefit to renting across from The University of Montana student housing on South Higgins. I can literally leash up my dogs, walk across the street, admire the ASUM community garden, and five minutes later be hiking up a mountain. Reason number 38 why I love Missoula – the outdoor accessibility.

Today’s hike up Mount Sentinel included an agenda: See how many cool Instagram photos I can snap and hike to an elevation height of 4,200 feet above the valley floor.

You can access this hike through the south end of the University’s Lewis and Clark student housing just off South Higgins Avenue. (There is also another trailhead off the corner of South Avenue and Maurice Avenue.) Once you are through the parking lot, follow a short, rocky/dirt road. You’ll pass the community garden, and you will see the trail straight up ahead.

Tip for this hike: Read up on the history behind Glacial Lake Missoula so that when you reach the high water mark, you will have a greater appreciation for the placement of the stone.

After the strenuous uphill climb, you will also have a greater appreciation for the person who had to haul that stone on his or her back to get it to that point. Actually, they used an ATV, but either way, Missoula should be extremely grateful to the Ice Age Floods Institute for its proposal and establishment of the 4,200 feet high water markers as well as to the City of Missoula’s Parks Board for permitting the request.

More tips for this hike: The best time to hike Mount Sentinel is late spring/early summer when the wild flowers are in bloom. Also, bring water for hiking this on warmer days because there is zero shade and it will seem as through you are walking straight uphill.

There are numerous trails on Mount Sentinel, but the quickest route to the high water mark, which evidently means the hardest, is to follow Mount Sentinel’s fire road until you reach Pengelly ridge trail. There are nicely placed signs along the way (see my cool Instagram gallery below). Follow Pengelly ridge upward and you will eventually see the high water mark to the west of the trail.

At this point take in the magical view of Missoula and try to picture a lake the size of Lake Erie and Lake Ontario combined.

Quite fascinating, am I right?



Before you lace up those hiking boots, check out more posts about walks and hikes in and around Missoula or visit the Make it Missoula hiking page.


KP enjoying Missoula's great outdoors

K.P. Nichols is currently interning for Make It Missoula. In the fall, she will graduate from The University of Montana with B.S. in Marketing. K.P. and husband, Josh, are originally from Nebraska, but moved to the mountains for the outdoor recreational opportunities and they absolutely LOVE Missoula.