COLORADO SUPERLATIVES

Long recognized for their exotic beauty and charm, southwestern Colorado's ancient cliff dwellings were designed to maximize human comfort in a climate subject to extremes. Their rugged cliffside setting certainly presented challenges for access - and undoubtedly provided some defense in an era marked by raiding and violence, even cannibalism. But these unusual buildings also show thermal characteristics that could inform contemporary design in our energy- conscious age.

Dating to 1260 and earlier, the cliff dwellings or alcove sites range in size from single rooms to complexes of more than 200 rooms, showing diverse forms and functions. Mesa Verde National Park contains more than 600 such sites, and the adjacent Ute Mountain Ute Tribal Park contains many more.

A cliff-dwelling construction boom of the mid-1200s corresponded with a climatic change marked by cold, wet conditions that evidence suggests prevailed in North America at the time. Colorado's southwestern plateaus today may experience annual temperature ranges from more than 100 degrees to minus 20 degrees Fahrenheit, so protection from winter's cold presents a challenge equal to finding shade from summer's heat. A snow cover of several feet is not unusual on the mesa tops. The challenges of winter would have been more extreme during the mid-1200s.

Choosing to live in a natural cliff shelter is an obvious way to gain protection from the wind, rain and snow. The rock walls absorb daylight heat and release it at night, and the curving, concave alcove walls and ceilings direct released energy toward the central living area.

Near-rectangular rooms were connected apartment-style, so that walls were shared and firewood fuel was used to best advantage. Blocks of rooms surrounded open plazas, and their walls radiated heat into these spaces undoubtedly used for daytime chores and social life. Most importantly, round semi-subterranean rooms, called kivas, were excavated into the rubble and underlying bedrock. These energy- retaining round structures were covered with multi-layer wood roofing, equipped with a central fireplace, and ventilated with a fresh air shaft and smoke hole. Park archaeologist Jack Smith and his colleague Duane Quiatt from the University of Colorado at Denver have clearly showed that, even without fires, a kiva structure within a cliff dwelling offered a far more stable temperature pattern than either cliff dwelling rooms or a kiva built in a mesa-top setting. When outdoor temperatures near Spruce Tree Ruin dropped below 0, air temperatures in the roofed kiva never dipped below freezing. A fire and the company of friends would have made this sheltered subterranean round structure a cozy place to pass the winter nights.

- Susan M. Collins is State Archaeologist for the Colorado Historical Society.

Copyright 1999
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