The Fiery Furnace

The Fiery Furnace, Arches National Park, April 2017.

Arches National Park in eastern Utah does not have any designated wilderness areas, but the Fiery Furnace is one specially regulated area that is accessible by permit only. It is located in the central region of the park near the main road that winds from south to north. Should one describe the Furnace succinctly, it might be called a labyrinth of rocky pillars.

Upon the suggestion of an acquaintance I met on the trail during my first day at Arches this past April, I checked in at the park’s visitor’s center to see if a permit for the Furnace was available. In fact, a permit could be had for the following day which was to be my last morning in Moab. Because I had plans to be in Mesa Verde NP by that afternoon, it had to be a quick visit of necessity.

Recent NAIP imagery of the Fiery Furnace area (from 2017
USGS topographic map). The parking lot and access trail to
the labyrinth of fins can be seen in the lower left corner.

The morning was calm and quiet with only a car or two in the parking lot of the Fiery Furnace. I entered the area via a short trail that led northward. Beyond that, permitted hikers were free to explore as they pleased, but regulations required visitors to walk only in sandy washes and on rocks to protect the more delicate geologic features such as soil crusts and sand dunes. Because I was unfamiliar with the area, I had no detailed map, and my schedule couldn’t afford the possibility of getting lost for any length of time, I decided that I would not wander too deeply into the maze.

The labyrinth of rocky fins at the Fiery Furnace formed from the same geologic processes that led to the creation of the iconic stone arches present elsewhere in the park. The fins resulted from ancient uplift of sandstone slabs that were underlain and pushed up by salt-infused mounds, followed by erosion of the uplifted rock along seams. The outcome: a series of parallel rusty red stone blocks set above the rest of the terrain. In the Furnace, the fins are oriented from northwest to southeast and have sandy gullies in between them.

At the start of my hike, I followed a wash at the western edge of the Furnace that was relatively open. It narrowed in places where one had to squeeze between rocks. Next I ventured a little deeper into the labyrinth, following a few small passages that meandered to the east and the north. I found a handful of markers for a self-guided loop trail that the Park Service had set up to guide visitors through the area. Along one of these shaded passages I passed under a small stone arch. The passage continued for a ways longer until it reached a terminus, boxed in by tall fins. At this dead end, a hole in the rock above created a natural sunroof.

Among the fins. At left a small sunroof in the sandstone rock can be seen in the top of a small alcove. At right: an arch I traveled under. 

Temporary sand sculptures crafted by light rainfall at night.

A light rain had fallen the night before my visit. In the sandy washes of the Furnace, there were little shallow saucers of coalesced sand gains on the otherwise smooth sand, the temporary sculptures of single rain drops. The other lovely sand features, as yet undisturbed from the footprints of human visitors, were animal tracks. Several types of fauna appeared to be involved in creating these, among them birds and lizards.

Vegetation wasn’t uncommon in the Fiery Furnace and it included pinyon pine and juniper, the common large woody species of the southwestern deserts. There were also other woody plants including two species of oaks and flowering shrubs of the rose family.

The narrow passages between the tall rock fins were shaded and cool and many probably seldom saw direct sunlight during the course of the day. In some of the more open areas of the Furnace, the crusts were more developed on the soil surface. These biological crusts (also called “cryptogamic crusts”) are a dark biological coating of living and dead organisms at the soil surface. Their biotic composition includes cyanobacteria, fungi, and algae (Pavlik 2008). The crusts provide stability to the surface soils, reducing erosion. Their other functions in the desert include storing nutrients and enhancing seed germination of vascular plants (Pavlik 2008).

Cryptogamic soil crust in the Fiery Furnace.

Having now seen enough to know that the Furnace is one of the gems of Arches, I hope to someday return for a time to get lost in the labyrinth of fins and alluring passages.

References

Morris TH, Ritter SM, Laycock DP. 2012. Geology Unfolded. An Illustrated Guide to the Geology of Utah’s National Parks. BYU Press.

Pavlik BM. 2008. The California Deserts. An Ecological Rediscovery. University of California Press, Berkeley, CA.

Fiery Furnace and with the La Sal Mountains in the background.

Animal tracks in the sand.