Wyalusing (WI) State Park Bluff Trail

The beginning of the trail
Image - Kris Lawson

Wyalusing State Park has many amazing bluff and prairie trails to wander up and down on. If you don't mind heights and a few vertiginous spots on a narrow bluffside trail - and are down for finding absolute carpets of spring ephemerals and a rare geological wonder, the Bluff Trail is a particularly stunning one to hike.

This short 0.9 mile trail begins in the large parking lot leading to the Lookout Point viewshed (just past the junction of Long Valley Rd). From the parking lot, you walk down a paved path to a spectacular view overlooking the confluence of the Mississippi and Wisconsin Rivers. Don't be surprised to get an eye level view of bald eagles circling on thermals on sunny days. There is also a marker commemorating Marquette and Joliet's landing in the 1670's.

So many wildflowers
Image - Kris Lawson

From the lookout, turn right and begin your descent to the trailhead. This hill is lush with ephemerals. Sharplobe hepatica, shooting stars, Jack-in-the-pulpit, bellworts, bishop's cap, anemones, trilliums and Solomon seal are just a few of the succession of forbs you’ll see in April through early June.

River views & steep slopes

At the trailhead, turn left onto a series of rock and wood/dirt steps that quickly descend over 170 feet to the fairly level but narrow dirt trail. On your left side are sharp drops but stunning views of the Wisconsin River and bluffs along the Mississippi River. On your right side, you will be treated to towering limestone cliffs and hillsides full of ephemerals.

Many of these limestone cliffs feature algific (cold air) talus (loose rock) slopes. They are a geological wonder. These rare, steep, north-facing slopes are found mostly in the Driftless region of Minnesota, Wisconsin, Illinois and especially in Iowa. The slopes vent out cool air during warm seasons. 

What causes these slopes and venting?

Outside temp

The habitat and ecosystem associated with algific talus slopes are the result of the limestone's slow erosion. That erosion creates porous fractures throughout the limestone. There is a slate or shale layer beneath the limestone that is impermeable.  So the water stays at that barrier and freezes during the winter. As it slowly melts in warmer weather, the water vapor and cooled air flow out of multiple fractures and vents in the rocks in the surrounding area. This cooler air results in a habitat supporting rare flowers and invertebrates that thrive in moist, cool environments and limestone soils.

Temp inside the cliff air vent

When I left a thermometer in one of the vents while we walked the trail on an out-and-back hike during a day in the low 80s, on our return to retrieve the thermometer, the air in the vent clocked in at 50F! That was a fun experiment.

Land snail shell

In my hikes on Bluff Trail in the last few weeks, these cool north-facing slopes were full of tiny mollusk shells, a profusion of bulblet bladderferns and shooting stars (which love limestone soils), great-scented liverwort and woodsy thyme moss among many other ephemerals including two-leaf miterwort, bellflowers, drooping trilliums, Jack-in-the-pulpits and smooth and false Solomon's seal.

Cool-air vents in the keyhole
Image - Kris Lawson

You can choose this out-and-back route for a pretty gorgeous 1.8 mile hike that affords spectacular river views on the way back. As you return, stand in the keyhole opening to the right of the initial first flight of stone steps.You will be blasted by cool air venting out as you stand there. From mid-May through October 1, you can pass through the keyhole to Treasure Cave down steep steps and then up steep steps into it. The cave is closed from October through mid-May. This is a bat hibernaculum for the little brown bat, a protected species.

You can also take advantage of other options to create a loop hikes from Bluff Trail if you prefer. These options include: 

• taking your first right up a steep hill to the campground road and hiking the road past campers and views (.8 miles on that part of the loop)
• continuing on to the second right on Old Wagon Road trail to make a loop to a parking area and following the road back (.8 miles on that part of the loop)
• turning left on Immigrant Trail and descending to the river level before heading back up to return to the parking lot (for an additional 2.6 miles). Caution: as of May 2026, the trail is temporarily closed due to flooding

No matter which way you take, don't miss the Bluff trail portion.You'll be glad you took it.

The confluence of the Wisconsin (right) and Mississippi (left) rivers

THE HIKE

A spring beauty still thrives in cold vented air

A short 1.8 mile out-and-back hike descends 174 feet down stone and wood steps to a narrow dirt trail along steep algific talus limestone cliffs. This vented cool-air habitat is a spring ephemeral and rare species paradise of lush growth and some rare limestone-loving plants. Spectacular views of the rivers and surrounding bluffs and communities makes the campground 200 feet above the trail feel miles away. An out-and-back hike on this trail is worth any brief vertiginous moment you may experience (pro tip: keep your eyes to the flower and fern covered slope if you do experience dizziness). Moderate due to slope and descent.

The Location
Wyalusing State Park, 13081 State Park Road, Bagley WI

Past the entrance's Visitor Center,  stay on the main road. After Long Valley Rd, take the first left into the parking lot for Lookout Point. The trail begins to the right of the lookout.

Images, unless notes - Marge Loch-Wouters

Bulblet bladderfern loves limestone soils and cool air vents

Looking for more area hikes? Please stop by the web version of the blog and under the "Labels" tab on the right hand side of the blog, click on "find-a-hike". There are over 75 hike descriptions and lists of hikes to try!

You can read my quarterly column on seasonal hiking suggestions in Inspire(d) Driftless Magazine available online or pick up a free copy at businesses and organizations around the Driftless areas of Minnesota, Wisconsin and Iowa.

Naturalist's Corner - What's Cool? What's Hot?

You may be expecting a post on the trendiest hiking gear or maybe climate change...

...but instead I want to reflect on two recent curiosities of nature and our seasons that I encountered. It's also about the delight we can find in learning - and learning more - on our hikes and interactions with nature.

The Cool

Northern-facing algific talus limestone cliffs

I spent time recently in Decorah, exploring a loop trail in Phelp's Park, especially at the start of its Trollkor's Trail. As we began our hike, we immediately went past a series of high limestone cliffs with a profusion of broken rock at the bottom and many small crevices and holes. Hmmm, what was this? We soon came upon a kiosk, detailing the algific talus slopes that are quite common in northeast Iowa. 

Checking out the cold-air flow

Then, past the kiosk, we noted large swaths of bright delicate fern moss covering the hillside. While moss isn't unusual at this time of year, the absolute masses we were seeing were. On that first hike on a 39F day, we were puzzled by this proliferation. 

It took a second visit, later in the week in much warmer 70F weather, to put two and two together. We were within touching distance of the north-facing algific (cold producing) talus (loose rock) slopes venting cold air from the beginning of our hike! Cool!

A chilly 55F in 71F weather

On that second warmer weather hike, as we passed the first short broken cliffs and the subsequent mossy slopes, we were blasted with cold air coming out of those vents.  The verdant moss on the hillside surrounded and covered those blast holes which were emitting 55F air. I had to hop into the sun after lingering there while confirming the temp! Our first hike was in air so cold we never felt the cold-air outflow. On a warm day, it was noticeably colder as we passed.

Ferns covering a vent

Living in the Driftless area, I have often heard about these slopes but never experienced them myself. According to the WI DNR biodiversity page, these steep north and east facing slopes occur when water enters through cracks in the limestone, freezes and slowly melts during the summer. It produces an outflow of cold air - a microclimate that supports rare plant and animal life. In general, these slopes are protected and not widely publicized to preserve their fragile ice age ecology.

So it was with great delight that I experienced their frosty air on a warm November day. I can hardly wait to return in spring and summer to observe what rare plants, within touching distance from the trail, prosper on these IA slopes  

THE HOT
Like many of you, with our early December snows, I often take snow cover for granted. It's there for snow fun, right?  But there's something special underneath the snow - the subnivean zone. It's a layer under the snow that retains heat throughout the winter and allows life to continue. Hmm, heat in the outdoors!

What's under that snow?

Subnivean is a such a lovely word that rolls off the tongue - and such an important piece of our winter landscape. The Latin roots of this word (sub and nivis) simply mean "below snow." After reading a recent post on naturalist Emily's Stone's amazing blog Natural Connections from the Cable (WI) Natural History Museum about the subnivean zone, my curiosity was piqued.

Over the years, I have seen spiders and snowfleas atop the snow and small tunnels and faint trails as the snow melts - all evidence that something was happening under the snow I hiked. We've all also probably seen, in nature photos and documentaries, foxes and owls honing in on small rodents beneath the snow cover. This subnivean zone provides an important part of winter survival for living things, from, as Emily Stone writes, "mice to martens, bacteria, fungi, spiders, hibernating insects, frozen wood frogs, and more."

Subnivean trails revealed in melting snow

So how does it happen? As the first substantial snow falls, it piles up on rocks, fallen trees, and vegetation that act like umbrellas creating space below. The snow cover creates a kind of thermal blanket and insulates the space. Those open spaces make up the subnivean zone. The temperatures remain constant at about 32F even if the air above the snow is much colder. Water vapor that forms from the earth's residual heat freezes at the bottom of the snowpack to create a type of ceiling.

Image - Emily Stone
Used with permission

In the photo at left from her blog post, Emily Stone writes: "All winter long I will monitor the air temperature and the temperature of a thermometer I recently buried in the Subnivean Zone under the snow. In it’s first day of existence this winter, the Subnivean Zone did not drop below 33 degrees!"

No wonder there is abundant life in that warmer zone.

It was delightful to spend time over the past few weeks learning more about both natural phenomena. If you want to dive a little more deeply, please check out some of the resources below:

Resources

The Cool - Algific Talus Slopes

A Global Treasure

 - Erica Place. Iowa Heritage Foundation. 2025

Karst Topography

 - Winneshiek County Conservation Board

Algific Talus Slopes

 - Wisconsin DNR

The Hot - Subnivean

Below the Snow

 - Ellen Horowitz. Montana Outdoors. March-April 2024

The Subnivean Zone: Shelter in the Snow

 - Barbara Mackay. Northern Woodlands Magazine. December 29, 2014.

Five Features of the Secret Ecosystem Under the Snow 

-Johnathan Pauli and Benjamin Zuckerberg. Grow Magazine, Spring 2024.

 Anaamaagon: Under the Snow: Exhibit Guide 

 - Cable Museum of Natural History, 2024

Images, unless noted - Marge Loch-Wouters

Standing in the 71F sunshine to warm up
after exploring the algific talus vents

You can read my quarterly column on seasonal hiking suggestions in Inspire(d) Driftless Magazine available online or pick up a free copy at businesses and organizations around the Driftless areas of Minnesota, Wisconsin and Iowa.

Phelps Park (IA) - Trollkor’s Trail Loop Hike

Some of the stonework on the trail

If you are looking for a great up-and-down trail loop with multiple interesting features, Trollkor's is a great 2.2 mile hike, spring through fall. With gun deer hunting season throughout November in WI and MN (IA's gun season starts in December), I figured it was a great time to swing over to Decorah IA to check the trail out. 

Decorah (population 7500) is rich in trails. According to their Park and Rec Dept., they have over 50 miles of hiking, walking, biking, running, cross country skiing and stroller-ing trails. The extensive trail system, centering on a series of limestone bluffs surrounding the Upper Iowa River, is a gold mine of recreational activities for locals and visitors alike.

There are a number of trailheads to start the Trollkor's loop but my favorite is at its west end off Hwy 52 at Oneota Dr.  There is tiny parking area at the dead end right by the trailhead marked by twin stone columns. This trailhead is on part of the 11-mile Trout Run Trail. It's wide, asphalt path accommodates bikers, runners, and walkers and is part of the Lower Phelp's Park trail as well. 

Upper Iowa River

On the left as you begin, the Upper Iowa River meanders. On the right, are low limestone cliffs full of small openings and broken rock at the base. Within 1/4 mile, there is a trail junction at a ravine near a kiosk with information on these algific talus slopes. You've just passed a few and there are more ahead. On warm days you can feel the cold air coming out of the holes in the limestone and see some amazing plant life on their north facing slopes. A marked trailhead climbs steeply up to the upper trails. But stay on the Trout Run trail for an easier access to the upper trails about 1/2 mile ahead. 

Prolific mosses grow over cold air
openings on algific talus slopes

The rock walls, with their cold air and massive swaths of delicate fern moss, are attention getting as the limestone cliffs began to tower above the trail. There is a lovely sculpture overlooking the river with small butterfly benches right before coming to a junction. Just ahead on the right off the paved trail are two more twin stone columns and a trail marker for the upper Trollkor's loop section.

Intricate herringbone pattern stonework

A quick 1/4 mile, 100 foot climb on a narrow, switch-backing dirt trail brings you to upper Phelp's Park. You are greeted by a short section of road with a fence of short columns stretching ahead with a complex of overlooks and stonework as you get to the main area of the park. The CCC-built rock columns are intricate and carefully crafted. A stone staircase descends down to the bluffside where the stone works (of art) feature carefully placed vertical stones in herringbone patterns and artfully chosen rock columns. 

CCC "LOTR dwarvish" earthworks

After passing through a long gazebo-like area, the rocky dirt trail continues beneath neighborhoods. You soon reach what to my eyes appears to be a series of Lord-of-the-Rings-style stone works. This well-engineered and CCC-built project leads down to a massive stairway and bridge crossing a ravine and following a stone-column railing to a final lookout. Be sure to note how seamlessly the stonework blends into the limestone cliffs. Masterful.

On the limestone cliff trails

Following the narrow cliffside trail west (hiking sticks are a plus on the trail's loose rock) affords great views of the river and prairie trails across the river. You soon come to a small trailhead that takes you steeply down to the Trout run trail. Don't take it, though, if you want to continue a great bluff hike.

Continuing on along the bluffside trail to your left, you cross bridges over ravines and hike upwards through a lovely clear understory. Once you cross a final bridge, you will climb a bit more through a buckthorn-filled part of the trail until you reach the top (you know you're on top because you hear traffic again). You'll then begin to descend slowly for 200 feet in a 1/2 mile along winding switch-backing trails that shift to pavement as you re-enter the neighborhood of Oneota Dr and spot your vehicle again.

THE HIKE
Trollkor's Loop is a 2.2 mile loop trail with a total elevation gain of 276 feet. The loop starts on a fairly flat  paved trail between the Upper Iowa River on the right and algific talus slopes (a naturalist's paradise) that morph to towering limestone cliffs on your left. At the end of the pavement, narrow switchbacks lead up to Phelps's Park and its stunning CCC-built stonework. The narrow rocky trails invite a hiking stick(s) as you walk atop the cliffs through cliffsides and across bridges spanning ravines. The loop ends with a slow descent into pavement that winds down to the Oneota drive neighborhood and your vehicle. This is a lovely trail with lots of features to return to and enjoy.

The Location

613 Park Dr, Decorah IA. There are also trailheads at the end of Main St to access the lower and upper parts of the loop and at Phelps Park above the city to access the upper portion.

Images, unless noted - Marge Loch-Wouters

Image  - Jean Hammons

Looking for more area hikes? Please stop by the web version of the blog and under the "Labels" tab on the right hand side of the blog, click on "find-a-hike". There are over 75 hike descriptions and lists of hikes to try!

A view of the Upper Iowa River
and prairie trails

You can read my quarterly column on seasonal hiking suggestions in Inspire(d) Driftless Magazine available online or pick up a free copy at businesses and organizations around the Driftless areas of Minnesota, Wisconsin and Iowa.