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Fantastic Places

A day at the Racetrack

This lesson aims to solve the mystery of the sliding rocks of the Racetrack Playa in Death Valley - a unique and fantastic phenomenon.

Key Concepts:
Place
Space
Physical processes 

Key questions:

  • Where is Racetrack Playa?
  • What processes could be responsible for the Sliding Rocks?

Where is Racetrack Playa?
Racetrack Playa is a seasonally dry lake (a playa) located in the northern part of the Panamint Mountains in Death Valley National Park, California, U.S.A. Death Valley is near the western border with Nevada, and is approximately 300km from Los Angeles. It is one of the many desert basins within the Sierra Nevada Mountains. 

What processes could be responsible for the Sliding Rocks?
Early investigators explained the phenomenon as the result of the rocks being embedded in an ice sheet in the coldest storms of winter. Being 1131 metres above sea level, the playa receives snow which freezes to a layer of ice at times. Ice rafts can form and it was thought that they could move across the playa lake with the rocks embedded in them. However, experiments to set up similar phenomena in 1996 did not fully support this theory. In 1998 investigators during an abnormally strong El Nino year with ice-sheets, did not show any movement of rocks from their mapped locations. Nevertheless, further measurements using very accurate GPS measurement instruments have found that there is a general movement trend towards the north-north east, which is the same direction that the prevailing winds move towards. Therefore, winds are the most likely cause of the trails in some way. The rocks seem to be propelled by the winds which have been made much stronger by being channelled through corridors in the south. 

Click on an activity:
Starter
Main activity
Plenary  

Downloads: 
Racetrack Playa Google Earth placemark 


Mystery cards “Why does Molly Move?” 

Sliding Rocks video

Fact Sheet: Desert processes and Death Valley

Images:  
Racetrack Playa
Sliding rock 1
Sliding rock 2
Sliding rock 3
Sliding rock close up
Source of the sliding rocks
Death Valley at night

Links:

You Tube video clip of flooding on Racetrack Playa:
http://www.youtube.com/watch?v=u1hoiHvOeGc

 

The Sliding Rocks of Racetrack Playa 
http://geosun.sjsu.edu/paula/rtp/intro.html

The Roving Rocks of Racetrack Playa:
http://www.larryo.net/RaceTrack.html

Sliding Rocks video
http://www.slidingrocks.com/ (click on DV Video)

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