Whiteout (weather) moving. Local, short-duration whiteout conditions can be created artificially in the vicinity of airports and helipads due to aircraft operations. Snow on the ground can be stirred up by helicopter rotor down-wash or airplane jet blast, presenting hazards to both aircraft and bystanders on the ground. Whiteout (weather) Whiteout is a weather condition in which visibility and contrast are severely reduced by snow or sand. The horizon disappears from view while the sky and landscape appear featureless, leaving no points of visual reference by which to navigate. Whiteout has been defined as: "A condition of diffuse light when no shadows
Irrational number A stronger result is the following: Every rational number in the interval formula_23 can be written either as "a" for some irrational number "a" or as "n" for some natural number "n". Similarly, every positive rational number can be written either as formula_24 for some irrational number "a" or as formula_25 for some natural number "n". It is not known if formula_26 (or formula_27) is irrational. In fact, there is no pair of non-zero integers formula_28 for which it is known whether formula_29 is irrational. Moreover, it is not known whether or not the set formula_30 is algebraically independent over