The heat of late summer and fall are sometimes punctuated by huge cloudbursts. In extreme cases, flooding has occurred when a year's total average rainfall was received in one storm. If this sudden runoff fails to find adequate channels and instead spreads out across the desert floor, sheet flooding occurs. What water is not absorbed in the gravels and sands will pond in the beds of Rosamond and Rogers Dry Lakes at the Valley's northern edge, where it eventually evaporates. A single storm may deposit much of this, with consequential rapid runoff and flooding on the Valley floor.
Earthquakes are even more potentially catastrophic to the Antelope Valley than flooding.
Indeed, the San Andreas forms the boundary between the North American continental plate on which the Antelope Valley sits, and the geologically distinct Pacific Plate on which the Los Angeles Basin sits. Four subsidiary faults, branches of the San Andreas, surround the Antelope Valley. In 1857, the massive Fort Tejon earthquake ruptured the San Andreas and displaced the plates by twenty feet in the Antelope Valley area. The scarp left by this quake is a major attraction for geologists. Climbing it, one can look into the roadcut where the Antelope Valley freeway passes through the scarp and see for oneself the terrifically deformed rock featured in so many geology textbooks.