Karst, caves and sinkholes


NOTE: In a sad coincidence, as I was writing this post, (a continuation of the last two posts—click here to go to the first in the series), a man in Florida was killed when a sinkhole opened up below his bedroom. Today’s post discusses the interpretive topics of the project I was working on in Southeast Alaska, including sinkholes.


Princes of Wales Island in Southeast Alaska is karst country. Karst is a landform that develops when water dissolves the carbonate bedrock, resulting in unusual features such as caves, sinkholes, shafts, disappearing streams and caves.

The following illustrations are details from the first sign of my project at Beaver Falls Interpretive Trail.


In limestone caves, features such as spires, pinnacles, soda straws, stalactites and stalagmites take thousands of years to form.

Soda straws are delicate, hollow tubes that hang from the cave ceiling, growing longer with each drip.


Eventually soda straws build up layers of minerals and become stalactites. Below, stalagmites form.















This detail from one of the signs shows the influence wetlands have in the development of karst.


Muskeg, or peat bog wetlands above ground contain very wet, acidic soils that are a catalyst in cave development. As the water flows through the muskeg, it sometimes flows sideways across layers of hard clay until it finds a way down through the porous limestone.

The entire sign.


A detail illustration from a sign interpreting the karst formation of sinkholes.


Sinkholes are etched into the landscape as water trickles down from the surface. The second illustration in the sequence shows what happens when the “roof” wears thin and suddenly collapses.

The full sign.


Trees in Alaskan karst tend to grow larger because the soil is rich and the limestone helps anchor the the trees against fierce storm winds.


Many animals use caves to escape harsh weather, find safe places to nest, give birth or hibernate. Some creatures spend their entire lives in the darkest interiors of caves.

A detail illustration of the many species that use karst caves.


The signs were installed on an accessible boardwalk trail above the cave.










To find out more about Prince of Wales Island and Beaver Falls Karst Interpretive Trail, check out:




The Pacific Northwest is not immune to sinkholes. In Shorelline, a city just north of Seattle, a giant sinkhole took out an intersection, just missing a nearby house. I designed some interpretive signs for the nearby park (written by Chuck Lennox). Check out the third sign in the series of project: Boeing Park

Further Adventures of Graphic Designer in the Wild

(This is part two of a three-post series. Click here if you missed part one)

…I watched him teeter toward us, disbelieving my eyes…

His legs bowed outward from the tops of his wobbly cowboy boots, and as he zigzagged down the dock, I was sure he was going to end up in the water. His hat was pulled down low and a shaggy gray mustache covered most of his sheepish grin. He looked like he had spent all night in a bar. Maybe more than one night.

“Charlie, you crazy old coot! You had some kinda weekend, huh?” The receptionist slapped him on the back affectionately. “Where’s yer bag, hon?” She grabbed his greasy-looking duffel and loaded it in for him. “Look, we’ve saved you the best seat!” She helped steady him as he weaved up to the little stool and climbed into the back of the plane.

I was such an idiot. Of course he wasn’t our pilot.

THAT was our pilot.

A tall, strapping young man was striding down the dock, and even from forty feet away it was clear that he was stone-cold-sober. Relief flooded me. Like all bush pilots I have flown with, this guy positively radiated calm, capable, no-nonsense efficiency and all-round good sense.

Alaskans are a bit kooky, but they don’t mess around with survival.

Just like that, my jitters vaporized. Welcome to Alaska.

For the entire trip, the pilot’s focus never wavered for a second. (Even with an annoying passenger sitting right next to him snapping a photo.)


The instrument panel of the deHavilland Beaver has a classic, almost art-deco style design. These planes were designed in the post WWII era specifically for flight in rugged and remote areas. They’re quite fun to ride in.


As the little plane puttered over the seemingly endless wilderness, I felt peace start to wash over me. For the first time since I had left Seattle, I felt truly relaxed. It was so nice to be far away from the insanity of 9/11.

The ride was a little bumpy through the occasional fog bank, but the winds were nice and calm..


We got to Thorne Bay right on time.


We landed, I made it up to the Ranger Station, met with my clients, took a little walk through town, and headed off to the place I would be staying. The couple who were renting me the room let me use the kitchen to heat up a can of chili, and we had a beer and talked about life on Prince of Wales Island and how much things had changed when the logging “stopped”. I’m on the environmental side of most resource-extraction issues, but I can understand how hard it is for people when their familiar way of life gets disrupted. Especially in a place like Thorne Bay, where the options are so limited.

But then, that’s why I was there, to make a small contribution to their recreation and tourist economy. Now—twelve years later—I wonder how they’re doing.


Thorne Bay is not what I would call charming, but it has a rough-around-the edges appeal.

You can find nice rooms to rent, either for a few nights or longer stays. People are very welcoming in this isolated little village.


Next week, I’ll tell you a bit about the real reason I was there…interpreting the fascinating limestone caves that lie hidden below beautiful Prince of Wales Island.

Click here for the next post in the series.








Graphic Designer in the Alaskan Wild

a Dahn Design, LLC True Adventure


“Welcome to Pacific Airways!” said the receptionist with a big smile. “Is this your first time in Ketchikan? What’s waiting for ya up in Thorne Bay? Gonna do some fishing?”

“No,” I said. “It’s business…just some contract work for the Forest Service.”

“Well, y’all should be leaving any minute…we’re just waiting for the pilot. Don’t worry, though, I’m sure he’ll roll in sooner or later.” She winked and smiled mischievously.

Alaskans are famous for their friendly, casual style. It’s part of their regional identity, the face they like to show the world. In the tourism industry, it’s practically an art—trying to get a rise out of Outsiders by being slightly outrageous. Europeans, especially, love this about Alaska, perhaps because it’s so refreshingly different from their own formal and proper culture. “Mein Gott,” they probably tell their friends back home,  “the martini came with a swizzle-stick made of real moose-droppings!”

It must be fun, being Alaskan.

Moose droppings


I glanced around the little waterfront waiting room to check out my fellow passengers. There was a pair of guys in grimy sports-camo with hunting and fishing gear, and several people I guessed were locals, loaded up with parcels of what looked like dry-good supplies. We weren’t a fancy bunch, but then this was no elegant cruise…this was an hour-long seaplane ride over the rugged Inside Passage on a de Havilland Beaver, commonly known as a bush plane.

The islands of Southeast Alaska are largely wild and remote, mostly accessible only by seaplane or boat. Loaded with salmon, brown and black bear, deer and mountain goat, it’s prime sportsman country, something that the Forest Service was trying to promote to offset the dwindling logging industry. It was part of the reason I was headed up there—to help them develop sports-tourism by designing some interpretive signs for their nature trails.

After all, when the bottom falls out of your resource-extraction economy, who do you call? Graphic designers, of course.

I settled into a plastic chair to wait, breathing deep to try to calm my nerves. It was silly, I kept telling myself. Nothing is going to happen. Of all places in the world, Alaska is probably the safest place to be…especially right now. Still, I had been feeling uncommonly jittery for a while.

Sixteen days, to be precise.

It was September 27, 2001—just two weeks and two days after the planes had crashed into the Twin Towers. Like most of America, I was still under the bad spell of it, still feeling twinges of shock and anxiety. It seemed like the whole country had ground to a halt and was sputtering to get going again, moving in clumsy slow-motion.

On the morning of my flight to Ketchikan, I had been stunned to find the airport in Seattle practically deserted. Not just quiet, but boarded-up, shuttered…dead.

I wouldn’t have been surprised if they had cancelled my flight, but the call for boarding had come as usual. There were only fifteen other passengers, and the Boeing 737 seemed eerily empty, especially because we were not allowed to sit near one another.

“Spread out evenly throughout the plane,” the loudspeaker ordered. “If you all sit in front, we could become nose-heavy.”

It wasn’t a comforting thought. This was the best Boeing engineers could do to keep their planes horizontal? Oh, we don’t bother too much about stabilization. We just order the passengers to spread out. Works fine.

Now, sitting in Ketchikan, I was feeling real jittery. Where was that pilot, anyway? If we didn’t leave soon, I’d be late for my meeting, and the whole project would get thrown off. On my first seaplane flight to Thorne Bay a few years earlier, we had been delayed for several hours because of bad weather—high winds, I think it was—and I had arrived late and missed my meeting. I wanted this trip to go more smoothly, in all respects.

Thorne Bay is pretty small, only a few hundred residents in a settlement that was once the world’s largest logging camp. From the air it looks like a cluster of buildings and a marina, surrounded by what seems like endless, unbroken wilderness, with countless islands, craggy coastlines, fiords, and thick forests that extend beyond the arc of the horizon. Southeast Alaska, and the Tongass National Forest in particular, are not necessarily pristine—there are plenty of human footprints from logging and other endeavors—but it is still a place where wildness is the rule rather than the exception. It is beautiful country.

From the air, Southeast Alaska seems like endless wilderness.


On that first trip, we had taken off from Ketchikan with three other passengers, dropping them off one-by-one along the way at what appeared to be isolated waterfront cabins, surrounded by mostly wilderness for as far as you could see. I wondered what it must be like to live in such places, so cut off from the rest of the world.

Taking off again after dropping someone at their isolated property (the cabin barely visible on the rocky shore).


By the time we reached Thorne Bay, I was the only passenger left on the seaplane, and the pilot swooped down, deposited me on the dock in front of the deserted-looking village, and took off again. My contacts at the Forest Service had long since given up waiting for me (this was before total cell phone connection) and I ended up wandering around the muddy streets of town with my pack, looking for the ranger district headquarters.

It must be around here somewhere…


Anyway, this trip, I wanted to be on time. I shifted around on the plastic chair and tried deep breathing again. Relax, I told myself. Even though this is a business trip, you’re in Alaska now—surrounded by friendly people and wild nature—far from the horrors of 9/11, those unspeakable images, the sorrow, hatred, bewilderment, the adrenaline-fueled debates. Here was nature…and peace. The peace of the wild.

Just breathe it all in.

The little crowd in the waiting room was certainly jovial enough. The receptionist was flirting with the hunters and the locals were laughing and joking with one another.

“Whadja tell her then? That you were flying in to go the library?” Wild laughter. “She’s gonna see the barstool imprint on yer butt, you know.”

His buddy grinned.“Yeah, well, at least I keep house with a human.” He spat a brown wad into a styrofoam cup. “What keeps you comp’ny at night?”

I was looking forward to hearing the reply, but the receptionist interrupted, “Okay everyone, let’s load up! The pilot is coming!”

We all lumbered down the dock to where the plane bobbed up and down in front of the little loading-stool. The hunters climbed into the back seats, and one of the locals ushered me forward politely. “Lovely ladies ride shotgun,” he said, with an exaggerated bow. “Thank you, kind sir,” I replied.

Good. I like to ride in front where I can keep an eye on the pilot.

But, where was he, anyway? The dock was empty now except for the receptionist who was helping us get loaded. Then she glanced back and yelled cheerfully “OH, THERE YOU ARE! Where the heck ya been?”

I followed her gaze to the end of the dock, and instantly, my jitters solidified into cold fear.

I watched him teeter toward us, disbelieving my eyes.

Oh. Crap.


Click here to go to the next post and read the exciting conclusion.