08-07-2025 Another Day Exploring, A Morning Kayak, a drive to Glass Mountain and a hike to the Medicine Lake Glass Flow

Early morning miasma on the lake with the air temperature at 34F

This morning, it was Deborah's turn to get out on the lake during the early morning stillness. There is no better time to be out paddling.  Even though it was cold when we got up, by the time we were on the water, the sun warmed us enough that we had to take off our jackets. 

Lots of delightful vignettes to during a slow paddle on the lake

Since we have paddled this lovely lake every single day, I thought I would share a little bit of geologic information.  Feel free to skip this part if it is too detailed.  I love this stuff and I think a few readers do as well.

Medicine Lake is a small lake just 4 miles wide and 7 miles long. It is nestled in a caldera that may have formed by collapse after a large volume of andesite was erupted from vents along the caldera rim.  No single large eruption has been related to this caldera formation. The only eruption recognized to have produced ash flow tuff occurred in late Pleistocene time, and this eruption was too small to account for the formation of the caldera. 

Deb and I were on the lake for a couple of hours, and the winds never came up

Later theories are that Medicine Lake caldera formed by collapse in response to repeated extrusions of mostly mafic (darker colored basaltic) lava beginning early in the history of the volcano, somewhat similar to the formation of Kilauea caldera in Hawaii. The small lake from which Medicine Lake volcano derives its name lies within the central caldera.

The broad shield volcano that forms the Medicine Lake Highlands began to grow about one million years ago, following the eruption of a large volume of basalt. During the past 11,000 years, eruptive activity at Medicine Lake Volcano has been episodic. Eight eruptions produced about 1.3 cubic miles of basaltic lava during a time interval of a few hundred years, about 10,500 years ago. That eruptive episode was followed by a period of calm that ended with a small andesitic eruption about 4,300 years ago. During the most recent eruptive episode between 3,000 and 900 years ago, there have been 8 eruptions.  

The area called Glass Mountain is large enough to be seen from miles away on Highway 139

Even though we have been there often, when we are in Medicine Lake, Mo and I usually take the back road drive to Glass Mountain, specifically to hike up to the best outcrop of black obsidian we have ever seen.  We were excited to share this amazing spot with Deborah, and after lunch, we piled into Deb's car for another back road trip.  Mattie was best left at home in the cool and safe MoHo, since hiking on shards of glass isn't good for little pup's feet.

Negotiating the rough, rocky tracks that are "trails" around the area can be tough

The goal is to stand next to this gorgeous obsidian outcrop

Glass Mountain is a large, solidified flow of volcanic glass, specifically obsidian, which is a type of volcanic glass formed from cooled lava. It originated from the eastern caldera rim of Medicine Lake volcano, with the lava flowing down the eastern flank of the volcano. 

Trying to manage a decent pose on the sharp glass outcrop can be challenging

Daughter Deb had a much easier time climbing around than I did

The flow is composed of rhyolite and dacite, which are types of volcanic rock. The formation involved an initial explosive phase with ash and pumice, followed by the oozing of thick, glassy lava flows. The Glass Mountain obsidian flow is relatively young, dating back about 950 years. 

Yesterday, from the top of Little Mount Hoffman, we could see Little Glass Mountain, in the photo above. It is a specific area within the larger Glass Mountain formation, known for its high flow front of broken obsidian and pumice. A few years ago, Mo and I drove down to explore Little Glass Mountain.  It was interesting, but not nearly as dramatic as Glass Mountain, with obsidian that was dark gray rather than pure black.

A photo I took in 2003 of the lighter colored obsidian at Little Glass Mountain

Something else I need to mention: In all the photos I have taken over the years, I have never seen any evidence of beetle kill in the area.  Sadly, if you look closely at some of our photos, you see brown and dying trees, mostly high-elevation lodgepole.  With increasing temperatures and repeating drought cycles, the trees can no longer resist the invasion.  It is a story that is happening throughout western forests from the Sierras in California all the way north into British Columbia and Alaska.  It made me sad to see this happening at Medicine Lake.

View of Medicine Lake from the Caldera Rim in 2003. No beetle kill in sight

Beetle kill in our campground at Medicine Lake

There is no quick fix for this problem on such a huge scale.  Most of the timber at this elevation isn't marketable, so timber companies aren't interested.  The US Forest Service is so overwhelmingly understaffed and underfunded that it cannot thin or burn, or even cut down the dying trees.  The last resort of using pesticides is much too expensive to consider. It is heartbreaking to see this happening in our beautiful Western forests. In 2022, in California alone, bark beetles affected more than 1.9 million acres of forest land. This is a significant increase from the 780,000 acres affected in 2021. 

Typical lunch: apples and peanut butter, cheese and crackers, chips and dip, and apples and carrots for Mattie

We returned to camp for a late lunch and an afternoon relaxing before going for a short hike just north of the campground to the Medicine Lake Glass Flow.  While not as dramatic as Glass Mountain, the edge of the Glass Flow is just a short .75 miles from the campground on an easy, mostly level hike on a nice trail.

It was perfect for Mattie, and we encountered no one else on the trail. It was ok to let Mattie off-leash since she minds well when called, and there wasn't another soul around.

After our hike and supper, it was time for...you guessed it...another beautiful campfire.

Once again we were treated to a magnificent show of sunset and a rising moon, with the lake reflecting the changing light and the sparkling moonlight on the water.  

Mo had me take many photos of that water reflection, trying to see the sparkle.  I discovered that a still photo cannot capture it adequately, and when I finally took a video, it was easy to see how the rippling water reflected the moonlight.

Originally, this was supposed to be our last night at Medicine Lake, but I got a wild idea as we sat by the fire, and we made the decision to extend our stay for one more night.  There was one more destination we wanted to share with Deb. Tomorrow I will write about our road trip and post the photos of the eagles I got on that last morning with the "real" camera.