Friday 8 Aug, 2014

Bryce Canyon’s Rare Treasures: Hoodoos

Hoodoos of Bryce Canyon

Hoodoos are the highlight of Bryce Canyon National Park.

When you visit Bryce Canyon National Park, you’re in for a special kind of sightseeing. This spectacular geological wonderland is home to an unusual kind of rock formation you can only find in a handful of places on Earth. They’re called hoodoos, and Bryce Canyon has thousands of them.

Hoodoos are tall spires of rock that can grow up to 150 feet high and are found mainly in hot, dry desert regions. What makes hoodoos special is their shape. Unlike your average rock spire or pillar, which tends to have a mostly uniform thickness or gradually thin out as you go up, a hoodoo has a variable thickness with all kinds of strange shapes from top to bottom. Many think they resemble totem poles, which is one reason humans have attributed a mystical quality to hoodoos over the millennia.

So how do hoodoos get their strange shape? It’s all through water erosion, mainly from frost wedging and rain.

Frost wedging
Throughout the year, Bryce Canyon goes through many cycles of freezing and thawing, and with each cycle the process of frost wedging continues to shape the rock in weird ways. Here’s how it works:

1. When snow melts, it seeps into the cracks and holes in the rock.

2. The snow re-freezes and expands, widening the cracks bit by bit. (This is similar to how potholes form in the road.)

3. Over time, as the expanding ice makes the cracks and holes bigger and bigger, the unusual shape of the overall rock formation becomes more and more pronounced. The hoodoo becomes more hoodoo-ish.

The other driving force in hoodoo formation—rain water—comes mostly from the short-but-intense summer monsoon downpours that wash away certain layers of rock. Since the hoodoos are made up of a number of different kinds of rock, those layers that are chemically more durable—like one called dolomite—tend to resist the rain erosion while the other areas are washed away. Again, the result is more unusual rock formations for visitors to marvel at.

Student trips to the National Parks allow you to discover the history of America from a whole new angle. Long before this country was born, long before humans even ventured onto this continent, mind-blowing natural forces were at work creating landscapes and formations that would be at home in any sculpture museum. And the hoodoos of Bryce Canyon are up there with the most spectacular of them all.