 The height of the range and the steepness of the Sierra Escarpment, particularly at the southern end of the range, produces a wind phenomenon known as the "Sierra Rotor".This is a horizontal rotation of the atmosphere just east of the crest of the Sierra, set in motion as an effect of strong westerly winds.Because of the large number of airplanes that have crashed in the Sierra Nevada, primarily due to the complex weather and atmospheric conditions such as downdrafts and microbursts caused by geography there, a portion of the area, a triangle whose vertices are Reno, Nevada; Fresno, California; and Las Vegas, Nevada, has been dubbed the "Nevada Triangle", in reference to the Bermuda Triangle.