The Movement of Playa Scrapers by the Wind

A theoretical discussion shows that it is possible for the wind to move rocks over a wet playa surface provided a sufficiently high pore pressure exists beneath the rocks. Measurements were carried out to determine the pore pressure which could exist under a rock on a muddy surface. The ratio of pore pressure to total rock pressure gave a range of 0.34 to 0.64, which would correspond to wind velocities of 45 m/sec (100 mph), to 33 m/sec (75 mph) for rocks having a large frontal area to mass ratio of .